Monster cookies are everything good that there is about cookie-baking and candy-eating. These classic cookies are loaded with peanut butter, oats, chocolate chips, and M&Ms; they bake up soft, chewy, and thick, and are absolutely irresistible!
If you’ve never made these classic cookies, then you’re missing out my friends! All of my favorite cookie flavors in one massive cookie. Seriously GOOD, extra thick with a soft texture and unbeatable taste.
They’re jumbo sized because they are jam-packed with tons of goodies and when it comes to cookies, bigger is always better!
What are monster cookies?
Monster cookies might have earned their name by their creator Dick Wesley, a photographer from Michigan State University, after changing his usual peanut butter cookie recipe. He was out of flour so he used oats and a mashup of other ingredients instead, including 12 eggs and 18 cups of oatmeal, making a HUGE dough.
It’s also believed they’re called monster cookies because they’re a combination of so many ingredients, just like the Frankenstein monster! And sometimes they’re known as “kitchen sink cookies” because they are loaded with everything but the kitchen sink!
The fabulous thing about these cookies is that they are totally adaptable to your tastes and you can go hog wild in creating the perfect cookie for you.
The best type of peanut butter and alternatives
I always, always recommend only baking with creamy, processed peanut butter, such as Jif, Skippy, or Peter Pan. Natural-style peanut butter with oil separation is simply too greasy for nearly all baking recipes; using it can result in cookies that spread too much and that can become crumbly.
If you’d like to use a nut butter alternative, see the recipe notes below on some recommendations.
Prepping the pans
My baking pans of choice are these rimmed half sheet pans; I have a ton and I use them for everything! And they are perfect for cookies.
I highly, highly recommend using parchment paper to line your baking pans when baking cookies. Greasing cookie sheets will allow excess fat to leach into your cookies, causing them to spread too much and potentially burn on the bottom.
For a brief time, I experimented with silicone baking mats, but over time found that they developed a greasy film that I couldn’t get rid of no matter how many times I washed in soapy water or ran through the dishwasher. It was causing the same issues as greasing the pan would, so I stopped using them and went back to parchment paper.
The fun starts here!
This recipe has the classic M&M and chocolate chips in it, but the possibilities are endless, they could be ANYTHING you want them to be! Here are some suggestions:
- Other Chips: Butterscotch, peanut butter, cinnamon, white chocolate chips, toffee bits, etc.
- Candy: Reese’s Pieces, chopped peanut butter cups, really any other chopped candy bar!
- Raisins, dried cranberries and cherries: For that extra chewy cookie, plump dried fruit is a great addition.
- Shredded coconut: This works especially well with the chocolate flavor combination.
- Rice Krispies: Will give that great extra crunchiness.
- Chopped Nuts: Add an extra layer of taste and texture.
- Cinnamon or Nutmeg: For the spice cookie lover!
- Cookies spread too much – This could be caused by a couple of things. You don’t want to grease the cookie sheet pans, use parchment paper instead. Natural-style peanut butter is too greasy, use creamy processed peanut butter instead.
- Cookies didn’t spread enough – There are a few things I can think of, the butter may be too warm when added into the batter; so try refrigerating the dough for 30 minutes before baking. Your oven wasn’t at the correct temperature, I recommend an oven thermometer.
- Cooking falling apart – The most common reasons cookies end up crumbly are using too much flour, be sure to either weigh your flour or spoon it into your measuring cup before leveling. Using the wrong kind of peanut butter may also be the culprit, be sure to see the note about peanut butter.
- Additional baking tips – You want to be sure you don’t over bake these amazing cookies. The cookies should be just browned around the edges and the centers still look soft and underdone when you take them out of the oven. They will set (perfectly!) as they cool. Let them cool on the baking sheets for a couple minutes and then transfer to a wire rack to finish off cooling.
Make-ahead, storage, and freezing tips
- Make-Ahead – You can prepare the cookie dough and refrigerate for up to 3 days before baking. When ready, let it sit on the counter for about 30 minutes before scooping and proceeding with baking.
- Storage – These cookies will keep in an airtight container at room temperature for up to 1 week.
- Freezing Instructions – These cookies freeze exceptionally well! You can freeze the baked cookies by wrapping them individually in plastic wrap, then place them in a ziptop bag and freeze for up to 3 months.
- Freezing the Dough – You can roll the dough balls and freeze them for up to 2 months. Bake for an extra minute or so.
More of my favorite soft cookies!
- $250 Neiman Marcus Cookies
- Thick and Chewy Chocolate Chip Cookies
- Peanut Butter-Oatmeal Chocolate Chip Cookies
- Soft and Chewy M&M Cookies
If you make these monster cookies and love them, I would so appreciate it if you would take a moment to leave a rating below. Thank you so much! ❤️️
- 3 eggs
- 1 cup (198 g) granulated sugar
- 1 cup (198 g) light brown sugar
- 1 teaspoon vanilla extract
- 2 teaspoons baking soda
- 1 teaspoon salt
- ½ cup (113 g) unsalted butter, melted
- 1½ cups (405 g) peanut butter, creamy or crunchy
- 4½ cups (446 g) traditional rolled oats
- ½ cup (60 g) all-purpose flour
- 1 cup (170 g) chocolate chips
- 1 cup (209 g) M&M's
- Preheat the oven to 350 degrees F. Line three baking sheets with parchment paper.
- In a large mixing bowl, stir together the eggs, both sugars, vanilla extract, baking soda and salt. Then stir in the melted butter and peanut butter, followed by the oats and flour. Lastly, stir in the chocolate chips and M&M's. Let the dough rest (at room temperature) for 30 minutes.
- Drop the dough by ¼ cupfuls onto baking sheets. Use your fingers to flatten the dough slightly. Baking for 15 to 17 minutes, or until the cookies are a light golden brown. Let cool on the baking sheet for 5 minutes, then remove to a wire rack and cool completely. Store in an airtight container at room temperature for up to 5 days.
- Baking Pans - My baking pans of choice are these rimmed half sheet pans; line with parchment paper.
- Nut Butter Alternatives - You can use other nut butters such as almond butter, cashew butter, etc. as long as they do not have oil separation (see the note above). A great almond butter substitute that works exceptionally well in all baked goods I've tried it with is Barney Butter.
- Mix-Ins - You can customize these cookies with different baking chips, candy, dried fruit, cereal, nuts, etc. See post above for specific suggestions.
- Troubleshooting - See post above for solutions to common issues such as cookies spreading too much or too little, being crumbly, and overbaking.
- Make-Ahead - You can prepare the cookie dough and refrigerate for up to 3 days before baking. When ready, let it sit on the counter for about 30 minutes before scooping and proceeding with baking.
- Storage - These cookies will keep in an airtight container at room temperature for up to 1 week.
- Freezing Instructions - Freeze the baked cookies by wrapping them individually in plastic wrap, then place them in a ziptop bag and freeze for up to 3 months.
- Freezing the Dough - You can roll the dough balls and freeze them for up to 2 months. Bake for an extra minute or so.
Did you make this recipe?
Leave a review below, then snap a picture and tag @thebrowneyedbaker on Instagram so I can see it!
[Photography by Ari of Well Seasoned]
I just made these tonight with dark chocolate chips, red and green m&ms, dried cranberries, and shredded coconut add-ins to kick off my Christmas baking before decorating the tree. They were huge, chewy, slightly nutty, buttery, and sweet-perfect. Thank you Michelle!
Hi, I am curious about an older version of this recipe. I thought the original one I made contained a small amount of corn syrup amd maybe a greater quantity of add-ins. I swear I got more raves from the older version and I even remember subbing honey for the syrup one time when some health nuts I feed freaked about corn syrup! Lol. Anyway would
Live some insight or the original if possible! Otherwise, I’ll have to continue making this AWESOME recipe! Thanks!!!!
This recipe is outstanding, the cookies turn out beautifully every time! Thanks for sharing the recipe.
We were about to have words because I am known for my Monster Cookies. Lol
Your recipe looks delicious and I will make a batch, you know, for comparison purposes. 😉
Really, I appreciate all of the recipes you have put out, they have helped during this heinous time.
Haha! I hope you enjoy these, and thank you for the super kind words, xo
When you make your Monster Cookies do you use quick oats or old fashioned oats. Thanks so much!!
Hi Diane, Old fashioned oats. Enjoy!!
Making these cookies again. Love, love love, this recipe! I made a couple batches for my daughters wedding rehearsal dinner and they were a big hit! Now I love to make them and freeze them to keep on hand when the cookie cravings strike!
I think these are my husband’s favorite cookies! They are so good. I sub butterscotch chips for the Reese’s pieces. Thanks for a great recipe.
These cookies are delicious and I have made them many times. Only problem I have is the bottoms of the cookies tend to start burning before the rest is done. Anything I can do to fix this?
I have made Monster Cookies for years and they are always a hit. These are so yummy, and can be made with any corresponding colour of M&Ms for festive occasions!
Also – in the version I use there’s no flour, so if you are careful about the other ingredients, particularly the oats, they are a great gluten free treat!
PS I created these cookies/recipe in my kitchen is Springfield, PA in 1983
I featured these cookies on my blog today for National Cookie Day! Thanks so much for sharing the recipe!
I usually make these for the boys who play intramural football at the university. I brought 3 dozen for 12 guys and they finished them all! That was even after feeding them sandwiches, chips, and oranges. These are definitely my favorite cookies to bake and always a team favorite.
I just used Reeses Pieces and white choc. chips and they are amazing!!
Sounds amazing! Glad you enjoyed them! :)
These cookies are no joke! I cleaned out my Halloween and Easter candy–pastel m&ms and whoppers in place of the reese pieces. They’re gone now!
I make a version of these without the flour and candy….basically PB and oatmeal cookies. Increase PB to about 2-2.5 cups, eat them warm with fresh whipped cream and raspberries….we call our version Evil Cookies because my thighs think they are..haha!
I’ve never heard of Monster Cookies before! I made mine with chopped up Flipz (chocolate covered pretzels), chopped up Kit Kat bars, M&Ms, and mini Reeses cups – the reeeeally small ones. I used about 3/4 cup natural peanut butter (it tends to make the cookies spread out more, because it’s more oily than regular peanut butter) but otherwise I followed the recipe to a T. Let me tell you… these things look and taste SO delicious! The perfect fix for a craving! I baked up one sheet full and I’m freezing the rest for future cravings! Thanks for this delicious recipe!!
I’ve been wanting to bake monster cookies all summer, and I finally decided to do so today. I am SO glad I did, and that I followed your recipe. These cookies are delicious and full of my favorite things. I used pretzel m&m’s because they are my new obsession, and while they are slightly bigger than the regular kind, the cookies were not too overloaded and came out perfectly. Thank you so much!
These are officially my favorite cookies ever! I love how chewy they are and how little flour is in them. I bake things for my dad all the time, but this is the only recipe he’s requested I make again! I can’t wait to try these with different mix ins :)
I am baking these right now but I don’t think they are coming out right and I am wondering what I did wrong! The dough is so stiff that when I put the flattened balls in the oven to bake, they basically keep that shape! It doesn’t seem to be spreading like most cookies. Has this ever happened to you before? I used all natural peanut butter since that is what I buy. Do you use all natural or something like Jiffy and do you think that would actually make a difference?
Hi Michelle, I actually never bake with all natural peanut butter because it’s texture is so different and it can definitely affect the outcome of baked goods. For baking, I stick with regular peanut butter, such as Jif.
If I wanted to go with a mint theme, do you think I could drop the peanut butter without ruining the texture or composition of the cookies?
Good basic recipe, though I modified it a bit. I didn’t melt the butter. I whipped softened butter with the peanut butter first, then added the rest of the “wet” ingredients. I next added this mixture to the “dry” ingredients. I also omitted the corn syrup and reduced the brown sugar by 1/4 cup and the white sugar by 1/4 cup. In order to encourage the cookies to spread a bit, I used a few wet fingers to press each of them down a bit before baking. Divine!
I tried yesterday this recipe, and we are already thinking in cooking it again, so you can imagine the success. The only “problem” is that, at home, I only had M&M’s with peanut, but I crushed them and it was also ok.
Thanks for the recipe, it’s really easy and very, very delicious!!
I love peanut M&M’s. They need to be hidden from me ;-) Great substitute!
I have always wanted to make Monster Cookies, and tonight, listening to the Monster Mash over and over with my 3 year old, I decided THIS was the night. My son was very excited to help make these, and sang Monster Mash the whoooole time. I made a few changes based on what I had- half butter half shortening, no corn syrup (I figured no biggie cause it was a tiny amount, but maybe it was a biggie?) and did chocolate chips, peanut butter chips, butterscotch chips and chopped pretzels! Now, I know it would be much better to have the candy coated kind because they are much more fun looking. But anyway, I used an ice cream scoop and got 36 cookies. I baked 6, thinking they would spread a lot, and they didn’t. they stayed in little mounds! After 12 minutes they were still totally balls. After 20 (yikes!) i decided to take them out. I cooled a bit and just ate one- yum. They are a little crisp outside and warm and soft inside- i hope they don’t get too hard as they cool since I baked so long. Do you think it was the shortening and lack of corn syrup that caused them not to spread?
Katie, How cute about your son singing “Monster Mash” while helping you bake! Love it! The shortening could have been the culprit here. I have seen it called for in sugar cookie recipes specifically because it keeps the shape of the cut out cookies, and keeps them from spreading.
My husband is very picky when it comes to Monster Cookies and he LOVES these! They turned out fluffy, soft, chewy, and oh so delicious! Thanks for the great recipe!
Yay! I’m glad these got your hubby’s approval!
Yum! There’s a reason your recipe pops up #1 in a google search for monster cookies! We made them tonight and they are so delicious! I’ve tried tons of different recipes, but your’s is definitely the best!
Thanks Londa! Great to hear your review, I’m so glad you loved these cookies!
Chocolate Chocolate Chip Cookies with Dark Chocolate Chips and M&M’s would be excellent. Or the Dark Chocolate M&M’s would be even better. Use really good chocolate and really good cocoa – the better the ingredients the better the taste.
Hey Michelle – I’ve made these a couple of times (so delicious!), but they seem to come out much flatter than yours. Any idea why this happens? Do you let the butter cool a bit before you add it…I’m thinking this might be my problem. Love your site!
Stop eating the mixture! These are a fantastic alternative to a standard choc chip cookie. I put in m&m’s and smashed up jaffas. Yum.
I tried making monster cookies before but they weren’t quite as I remembered. These look like they might be closer to the ones I used to have. Swapping out the butterscotch chips for Reese’s Pieces sounds perfect to me. I’ve seen these Almond Joy pieces that I’ve been intrigued about and I’m thinking they might be yummy in here!
YUMM! These look great, I think I would even add in some marshmallows in there to seal the deal! And about those no-bake cookies, I think I go to that recipe everyday and dream of how good and easy they look, except the hubby doesn’t like oatmeal so I haven’t made them yet!
What pretty Monster cookies…They look so good!
I remember making these a lot as a kid. These bring back some good memories. I just might have to make a batch soon.
how crazy cookies :)
I LOVE monster cookies, these look delicious!!!
Love the look of these cookies. So fun!
There is a local coffee shop here in Vancouver that makes it’s own monster sized cookies. Orange cranberry with white chocolate chunks. I could eat myself silly on those if I still worked next store to that shop.
Fantastic monsters you have out there! They look good and very attractive too!
These look awesome! When I used to work at Southern Living Magazine, we made these all of the time. Your version looks wonderful. Love your site!
i’ve made a version of “monster cookies” before… but yours look amazing! never thought of reese’s pieces! yumm!
I love monster cookies! A little bit of everything. :)
Just bought a few packs of Pretzel M&M’s (had 2 buy one get one free coupons) which I think would be fab in these Monsters. Sounds like the perfect ride-out-the-edge of Tropical Storm Alex baking project.
What fun! I love how colorful they are! These look like Wonka cookies to me!
I’m going hog wild for yours!!
These are gorgeous cookies. My husband will truly love these, especially that you mentioned peanut butter, that is his favorite.
I love monster cookies! The Reese’s Pieces make an awesome addition…I’ll have to try that next time!
Wow these look amazing!! I’m such a cookie monster – this is going straight to the top of my to bake list. Thanks :)
I tried a mix for Monster cookies that added raisins and peanuts and we were not impressed. I’ll settle for just a multitude of different chocolates thank you very much.
These cookies look awesome! I would love to enjoy a few of these with a cold glass of milk!
These are great with the M&Ms peeking out… how can any kid (of any size and age!) say no to these?
These monster cookies look Fab, I will have to give them a try next time I bake cookies, we seriously love some Reese’s Pieces at our house!
These are more filling than cookie! What a wonderful recipe for kids – I’m sure this would be fun to mix and bake together (and, of course, eat them!)
Love it! I can’t wait to experiment with my own! :-)
I’ve made these before and they are delicious. Nice and chewy but soft and scrumptious. Now you got me thinking that I need to make them again!
This is such a classic recipe. I loved having these as a kid!!
Yum— these make me want to break into the highest part of the pantry where the m&ms are “hidden” and get baking! Everything you create is so pretty and inviting, and these little cookies are no exception. Can’t wait to see what’s next.
– Lauren, Lauren’s Little Kitchen
Thanks for sharing the yummy cookie recipe! My son would love these.
I love cookies that have tons of add-ins. The recipe and pictures look great! I’m heading to a friend’s house this weekend for a BBQ and will have to take these along for the ride.
I think I spotted a puddle of drool under my office chair…..
Peanut butter oatmeal chocolate chip cookies — the best!!! Ur add-ins only make this taste sensation sound even better!!!
I am making these tonight!
these look great… your recipe looks wonderful & sweet….& a great way to use up chocolates, chips etc.!
i am going to prep/ assemble & freeze the dough balls…& bake fresh out of the oven for july 4th!
Will have to try these cookies…they would be festive with red/white/blue M&Ms. Try looking at Walmart for the different colors M&Ms…I’ve seen them in individual tubs – sold by color. They were located where the large packaged candies are displayed. If you have a Michael’s in your area, they also sell them – individual tubs. They are on the “high” side, but at least you get what you want.
You can also buy red/white/blue sprinkles in a small plastic container.
Thanks for sharing your wonderful recipes!!
Hi Judy, Thanks for the tip! I did look at Wal-Mart for the M&M’s in the section you mentioned but didn’t find any. I didn’t check Michael’s though, I will definitely do that next time!
Try the candy section at Wegmans also (if you have one) I believe they sell M&M’s by color in the Bulk Section! Party stores like Party CIty carry individually colored M&M’s but they’re $7.99 a bag (in Northern VA anyway).
Thanks Judy for the Pretzel idea. The man will LOVE that.
Didn’t this recipe used to have corn syrup in it? How much? That’s how I always made them.
I once had a cookie like this that had chopped pretzels in it. Tasted so damn good!