Peanut Butter Cup Cake

Today, I turn 34 years young, and I have the most serious of serious questions to ask. Does this mean I’m now in my mid-30’s? If the answer is yes, don’t tell me. It dumbfounds me to think that at 34 years old, my mom already had a 9-year-old and a 7-year-old. I barely feel like a grown-up, save for the mortgage payments and general responsibilities that come with not being 18 anymore.
If time is going to keep on moving, we might as well welcome it with open arms and some phenomenal cake, right? I have had this cake on the brain for months, but decided to shelve it and save it for my birthday. I couldn’t think of anything more perfect for me than an overdose of chocolate and peanut butter to the highest degree.

I basically took my favorite chocolate cake, my favorite peanut butter frosting, tons of peanut butter cups, and smooshed it all together into one of the most fabulous cakes I have made to date.
For someone who could eat chocolate and peanut butter for breakfast, lunch and dinner, this cake is a dream come true.

The cake is the same one I used for my Snickers cake last year; do you remember how much I went on and on about how it’s the best chocolate cake ever?
Well, it’s still the best chocolate cake ever.
Case closed.
Save This Recipe

The peanut butter frosting is a double batch from my chocolate-peanut butter cupcakes, and I love it because it’s silky smooth, super peanut butter-y and not at all too sugar-y. I would love to just eat it from a bowl with a spoon. However, I’ll settle for it on this cake along with tons of chopped peanut butter cups, because, of course, there needs to be peanut butter cups.

I plan to spend my birthday relaxing, going to a hockey game, and eating a ridiculous amount of dessert.
That’s what birthdays are for, right?

One year ago: Italian Easter Pie
Three years ago: Tiramisu Cupcakes
Four years ago: Easy Vanilla Bean Buttercream
Six years ago: Slow Cooker Beef Burgundy
Watch How to Make the Peanut Butter Cup Cake:

Peanut Butter Cup Overload Cake
Ingredients
For the Cake:
- 2½ cups (312.5 g) + 1 tablespoon all-purpose flour
- 3 cups (600 g) granulated sugar
- 1 cup (86 g) + 1 tablespoon Dutch-process cocoa powder
- 1 tablespoon baking soda
- 1½ teaspoons (1.5 teaspoons) baking powder
- 1½ teaspoons (1.5 teaspoons) salt
- 3 eggs, at room temperature
- 1½ cups (360 ml) buttermilk, at room temperature
- 1½ cups (355.5 ml) strong black coffee, hot
- ¾ cup (163.5 ml) vegetable oil
- 4½ teaspoons (4.5 teaspoons) vanilla extract
For the Peanut Butter Frosting:
- 2 cups (240 g) powdered sugar
- 2 cups (516 g) creamy peanut butter
- 10 tablespoons unsalted butter, at room temperature
- 1½ teaspoons (1.5 teaspoons) vanilla extract
- ½ teaspoon (0.5 teaspoon) kosher salt
- ⅔ cup (158.67 ml) heavy cream
For the Chocolate Ganache:
- 8 ounces (226.8 g) semisweet chocolate, finely chopped
- ¾ cup (178.5 ml) heavy cream
- 30 miniature peanut butter cups, coarsely chopped, divided
Instructions
- Make the Cake: Preheat oven to 350 degrees F. Grease three 8-inch round cake pans, line the bottoms with rounds of parchment paper, grease the parchment, then flour the insides of the pans, tapping out excess; set aside.
- In the bowl of an electric mixer (or large mixing bowl if you’re using a hand mixer), sift together the flour, sugar, cocoa powder, baking soda, baking powder and salt. In a medium bowl, whisk together the eggs, buttermilk, coffee, oil and vanilla.
- Add the wet ingredients to the dry ingredients and mix for 2 minutes on medium speed. Scrape the sides and bottom of the bowl and mix for an additional 20 seconds (the batter will be very thin).
- Divide the batter evenly among prepared pans. Bake for 20 minutes and rotate the pans in the oven. Continue to bake until a toothpick inserted into the center of one of the cakes comes out almost clean (with a few moist crumbs), about 12 more minutes. Cool the cakes (in the pans) on wire racks for 20 minutes, then carefully turn them out onto cooling racks to cool completely.
- Make the Peanut Butter Frosting: Place the powdered sugar, peanut butter, butter, vanilla and salt in the bowl of an electric mixer fitted with a paddle attachment. Mix on medium-low speed until creamy, scraping down the bowl with a rubber spatula as needed. Add the heavy cream and beat on high speed until the mixture is light and smooth (do not overbeat).
- Assemble the Cake: If your cakes baked up uneven or have domed on top, level off the tops. Place one cake layer on a serving plate. Cover with 1 cup of the peanut butter frosting and sprinkle 10 of the chopped peanut butter cups over the frosting. Top with a second cake layer and cover with another 1 cup of the peanut butter frosting, and top with another 10 chopped peanut butter cups. Place the final cake layer on top face-down. Frost the cake with the remaining peanut butter frosting, finishing it as smoothly as possible. Refrigerate the cake for at least 1 hour, until the frosting is set.
- Make the Chocolate Ganache: While the cake chills, make the chocolate ganache. Place the chocolate in a 4-cup measuring cup; set aside. Place the cream in a small saucepan over medium heat and warm until it just comes to a boil. Pour the cream over the chopped chocolate and let sit for 2 minutes. Begin whisking the mixture in the center, gradually working your way outward until the ganache is completely smooth. Set aside to cool, whisking occasionally, until it has thickened slightly, yet still a pourable consistency.
- Garnish the Cake: If the ganache was mixed in a bowl, transfer it to a 2-cup measuring cup. Slowly pour the chocolate ganache into the center of the cake, letting it push itself outward and flow over the sides of the cake. Top with the remaining 10 chopped peanut butter cups. Refrigerate the cake for at least 30 minutes, giving the ganache a chance to set up. Keep the cake refrigerated, removing it from the refrigerator about 20 minutes prior to serving.
Notes
Did you make this recipe?
Leave a review below, then snap a picture and tag @thebrowneyedbaker on Instagram so I can see it!



Happy birthday! You are almost exactly eight months older than me, so mid-thirties or not, I’m close behind you. I don’t have kids as old as your mom did at this age, but I do have two kids in addition to the mortgage and other adult-ish responsibilities, and trust me, kids do nothing to make you feel more like an adult!
I actually do not like chocolate cake–but this one looks like it’s fudgy enough that it would be good for me (the thing I dislike about chocolate cake is the light, spongy nature of so many of them) and I can usually eat chocolate cake if it’s covered in frosting that is peanut buttery or minty. Chocolate + peanut butter is always a winner!
Now THIS I need to try!
Happy Birthday! Mine was yesterday! I’m looking forward to making this as EVERYONE in my office loves chocolate and peanut butter. I know this will be a big hit!. Thanks for all the amazing recipes!
Happy, happy birthday!! I’m kind of jealous that you get to spend it with this cake – it looks phenomenal!!
Happy Birthday! That cake looks amazing. I love chocolate and peanut butter! Can’t wait to make it.
Happy Birthday!! I found my sons birthday cake for when he turns 18 next month. Thank you and enjoy your day!!
Happy birthday! My birthday is Saturday and I think I will need to make myself this cake. We are celebrating with a Red Wings game next week. And don’t worry about 34 being mid-thirties. I am convinced 36 is still mid-thirties too!
This cake is so full of deliciousness! I love this recipe!
Is there any way i can omit the coffe ???
Hi Madelynn, I really don’t recommend it; it’s a key ingredient in the cake, adding moisture and enhancing the chocolate flavor. You can’t taste it at all.
So I don’t drink coffee for religious reasons but this cake looks amazing, so I was wondering if you could think of any subsitutes? I know that coffee is commonly used with really chocolatey things so if you know a good subsitute that would be really helpful in general.
Hi Elena, Is it due to the caffeine content? If so, you can certainly use decaf. Unfortunately, I don’t know of a suitable replacement since water would dilute the flavor, milk would add extra fat, possibly affecting the texture of the cake, and hot chocolate would add extra sugar.
Elena- I don’t drink coffee either. I’ve used coffee flavored Postum or Pero in other recipes and that’s worked. I’ll be making this cake later today and will be doing that substitution. I’ll post back with the results.
I made it with water in place of coffee. I can’t say how it compares, but I can say it was delicious and still very chocolatey. It doesn’t taste like it’s missing anything to me, and unless you had a side-by-side comparison, I don’t think anyone would complain.
This looks delish! How strong is the coffee flavor? I do not like coffee. Wondering if I could leave it out of the cake recipe? Happy Birthday!!
Hi Sarah, You can’t taste the coffee at all! I don’t recommend leaving it out as it helps to add moistness and enhances the chocolate flavor.
Happy “29th” Birthday! You’re as young/old as you feel. No labels.
Just saw your cake on PARADE website. How exciting!
Happy Birthday, Michelle! Hope your day and upcoming year are full of joyful surprises! Thanks for all the delightful recipes, especially this amazing cake!
:)
Happy Birthday, Michelle. Your cake is perfect for the occasion (as well as any day of the week). ;) It looks so yummy. Hope you have a wonderful day.
Happy birthday! I hope you have a wonderful day. :) Your blog is one that I read every day- thank you for all that you do. This looks delicious!
First of all, happy birthday! Secondly, this looks AMAZING!! But, unfortunately I can’t have it, because I gave up chocolate for lent. I know,I know, I’m crazy, but I’ve gotten used to it. After Good Friday this is definitely on my to-bake list! I hope you have wonderful birthday!!
Happy Birthday to you!! The cake looks Delicious! Thank you for having one of my very favorite food blogs. I sure do appreciate all you do for us foodies. 34 is young, and it sounds like you feel that way. Wishing you many more.
Happy birthday, Michelle! This cake is the PERFECT way to celebrate. I might just have to make it this weekend to celebrate my own birthday… a month and a half early. ;)
Happy Birthday! It’s like you know I’ve been obsessed with making three layer cakes, or else why would you post this delicious recipe to tempt me?? Unfortunately my kitchen is being renovated so baking anything right now is a huge hassle. I’ve been on a chocolate cake kick, trying a bunch of different recipes. I’ve found two others that were very good, so I’m excited to try this one as well. The frosting you used for this cake is actually my go-to peanut butter frosting! It can’t be beat.
Happy birthday! I may just request this cake for my own birthday next week! Thanks for sharing!
Happy birthday! I’ll be 18 in a couple of days and this looks like a serious contender for my cake…
Happy birthday, Michelle! If this cake tastes anything close to as good as it looks, I want to eat the entire thing right now!
34 years young! Happy happy birthday! Thank you for sharing this amazing cake, I think I will “save” it for hubby’s birthday in October!
Hi :) its my husbands this weekend and I really want to try baking this cake, I have one question, would it be OK to replace the buttermilk with yoghurt? I usually find it difficult to get hold of buttermilk :) thanks for the amazing recipe
Hi Safia, I have not tried to make that substitution and am not sure how it would affect the batter, so unfortunately I can’t say one way or the other. You can always make your own buttermilk with regular milk and lemon juice: https://www.browneyedbaker.com/substitutions/
Happy Birthday friend! I am drooling over this cake. The best way to celebrate! xo
I would definitely want this as my birthday cake! Happy Birthday Michelle!
Happy birthday to you. I bet you’re the only person in your life that bakes like you do, otherwise somebody could have made you a cake for once :-P I mean that in a good way, because this blog is amazing.
Happy Birthday!!! I know exactly what you mean about barely feeling like you’re grown up. I’m 31 and sometimes I really have to think when someone asks how old I am because I still feel like I’m still in my early 20’s! I hope you have a great birthday!! That cake looks absolutely AMAZING!!!!
This looks so freaking amazing. Making this ASAP! Happy Birthday!!
Happy birthday, Michelle! This is the perfect way to celebrate. This cake looks SOOO amazing. I am going to bookmark this to make for my husband’s birthday in May – this is a dream cake for a choco pb lover! Hope you have a fabulous day!
Happy Birthday Michelle! Your cake and photography get me in the Cake Mood! I am Not a cake person, rather a pie girl so Kudos to You! Your age is only how you feel and what people perceive! You are young and young at heart and will probably look & feel young when you are in your 70’s! Enjoy life and your loved ones!