How to Make a Rainbow Cake
97 comments » 
This past weekend I made a 2nd birthday cake for the nephew of one of my best friends. The decorations they wanted were fairly simple – a lot of bright, primary colors (much like what was used on the clown smash cake), with a train track running around the outside of the cake. The train set on the cake was used on birthday cakes when the little boy’s mom and aunt were little, and they wanted to continue the tradition. The track ended up being the perfect size to set the train on! But the real magic of this cake was on the inside… a rainbow cake!
I have made a few children’s cakes like this before, and have been asked how it’s done, so I thought it was high time that I put together a tutorial for you. It’s such a fun, whimsical way to brighten up a child’s birthday cake, and is incredibly easy to do. Below are the step-by-step instructions with photos. Have fun!
First up, you’ll want to have your favorite white cake recipe handy. My personal favorite is the Perfect Party Cake, but any of your favorite recipes will work, and you could always use a box mix too, if you prefer.
A quick note on cake recipes… I always use this Cake Batter Chart from Wilton when baking cakes that I’m going to decorate. They call for more batter than you would typically use, but the cakes bake up nice and tall and, once leveled, create wonderfully high layers. Not only is more cake better for everyone, but you have more space on the sides for decorating! To give you some perspective, a typical recipe for a 2-layer 9″ cake yields anywhere from 4 to 5 cups of batter.
Now, grease and flour those cake pans!
Next, mix up the batter for your cake and get 6 bowls (or your fanciest plasticware) ready…
You want to evenly divide your cake batter between the 6 bowls/containers. The best way to do this is to measure the batter into a large (4-cup) measuring cup (might have to do this two or three times) or to weigh the batter, and then do a quick “divided by 6″ to get the amount you should be scooping into each container. This is probably the hardest part of the whole process 
Now, round up your food coloring – liquid or gels. A lot of people have said they have great success with the AmeriColor gels, but I still had some liquid food coloring from other recipes to use up, so I went that route.
Time to color away! You’ll want to make the fun rainbow colors, naturally: red, orange, yellow, green, blue and purple. If you’re using the little 4-color kit like me, just combine red + yellow for orange, yellow + blue for green, and red + blue for purple.
Use as much as needed to get the color hue you’re going for. (Alternately, you could really do this for any color combinations you’d like. You can keep half plain white and the other half brown to do a zebra. Reader Julie on Facebook mentioned she saw a cake like this with varying shades of pink, and you could definitely do that as well.)
Now, we’re ready to load up the cake pans. You have two options here:
Option #1: You can make one cake layer red, orange and yellow, and make the second layer green, blue and purple. I chose to do the cake this way so that the individual colors really popped and you could see all of them really well.
Option #2: You can do all six colors in each layer. To do it this way, divide each color in half between the pans. So, half of the red would go in one pan, and the other half in the other pan, and then proceed the same way.
As I mentioned, I used Option #1, so that’s what you’ll see illustrated here. First, pour the red batter into the bottom of the cake pan.
Next, add the orange batter on top of the red. Slowly pour the batter into the middle of the pan. As you do so, the red layer below it will spread out.
Finally, pour the yellow batter in the same way you poured the orange.
Repeat the process in the other cake pan, starting with the purple, and then adding the blue and green.
Bake those babies up!
Once the cakes have completely cooled, I like to wrap them in plastic wrap and refrigerate them for at least an hour. I find that it’s much easier to level cold cakes then room temperature ones. They are firmer and don’t crumble, making for a cleaner cut.
I use this Wilton Cake Leveler to level my cakes. It’s super cheap (less than $5 – you can find them at a place like Michael’s), and makes it incredibly easy to make sure the cakes are sliced evenly and cleanly.
Here’s what the tops of the cakes looked like after they were leveled… so colorful!
At this point, I went ahead and filled the cake and then decorated it.
I received a couple of questions on how to make the train tracks on top of the cake, so I’ve included that short description below as well.
How to Make Train Tracks
My friend told me that the tracks needed to be ¾-inch wide in order to accommodate the plastic trains that they wanted to decorate the cake with. I used brown fondant rolled out to about 1/16-inch thickness, and then cut a long strip ¾-inch wide. From there, I cut across the strip in ¼-inch increments until I had as many “tracks” as I needed.
Once I was ready, I spaced them evenly around the cake. To make the rails, I used a #2 decorating tip with black icing.
And here was the finished cake, before it went out for delivery and got adorned with the adorable train set that you saw in the first picture.
(Thank you to my friend Renee for snapping those pictures for me so I would have photos of the cake with the train on it, and the inside of the cake once it was cut!)
I hope you enjoyed the tutorial!
Such an adorable birthday cake! I really love all the colors in rainbow cakes…I just need to break down and make one!
Reply
Wow – that is such a beautiful cake! Love it!
Reply
Wow that looks fantastic and a real surprise when you cut into it. I think this is much prettier than having multiple layers. It really looks swirly and rainbow like. Beautiful
Reply
This is such a cool recipe. It looks so fun and delicious too! Love the colors!
Reply
Such a adorble cake.
Reply
This is the coolest cake I have seen. This tutorial came in the nick of time. My god daugther wants confetti cake for her birthday so I am thinking this will probably be my guide for her cake. Wonderful cake once again. Saved it
Reply
Wow, it looks great and so simple! I’m definitely going to try this next time I have to make a cake for a small child. Or indeed a big one
Reply
I love the rings of colours. Thank you!
Reply
I’ve wanted to make one of these for a while! They look so yummy!
Reply
Fabulous, this is definitely on my to bake list – thanks for the tutorial!
Reply
Gorgeous! Can’t wait to try this!
Reply
This is so adorable and seems so manageable. I love the idea of surprising people when they cut into the cake. Can’t wait to try it! Do you think it could also work for cupcakes?
Reply
Michelle on September 18th, 2011 at 3:04 pm
Yes, absolutely!
Reply
Can you do this for cupcakes? If so how many would you get?
Reply
Michelle on September 18th, 2011 at 3:05 pm
Hi Dawn, Yes! You would just divide the difference colors between the cupcake liners. Lisa shared how she did this (with a picture) on the Brown Eyed Baker Facebook page: http://www.facebook.com/photo.php?fbid=10150796845745247&set=o.91519478473&type=1&theater
Reply
I’ve always been fascinated by rainbow cakes! This recipe makes them feel achievable! Thanks.
http://allykayler.blogspot.com/
Reply
This is so awesome! I made rainbow cupcakes a little while ago the same way
Love your blog!
bsweetdreaming.wordpress.com
Reply
This is so cool! There’s not many food items that I say that about
What a fun idea…I’m sure the birthday boy loved it!
Reply
WOW! Yours is much easier than mine. I did mine in each layer, which made my cake REALLY tall – almost too tall to transport well and made it take much longer since I had to bake the layers in pairs because that’s all the cake pans that I had. Well done!
Reply
you’re an old pro!! this looks amazing!
Reply
Wow, this is beautiful. The colors are so vibrant! Now I am craving some cake.
Reply
Incredible!!! I’ve been wanting to try this. Thanks for the detailed tutorial!
Reply
wow and once again wow thats all I can say!! It is my first time when I see such a beautiful rainbow cake, and I plan making it for my husband birthday it will be something different! it looks really yammy!
Reply
If this isn’t the cutest most original rainbow cake I’ve seen then I don’t know what is. What a lucky little birthday boy. I’m sure he was grinning from ear to ear when this arrived.
Reply
So pretty! Is there something around the purple? Or is that just crusty part from baking?
Reply
Vadigor on September 15th, 2011 at 6:31 pm
I’ve made one of these before and confirm that it’s simply the crust. Due to the Maillard reaction the original colour will darken, brown and possibly discolour so you may want to be careful with what colour you have on the outside.
Reply
Michelle on September 18th, 2011 at 3:12 pm
Just the crusty part from baking.
Reply
What a pretty cake! I think everyone needs a rainbow cake in their life.
Reply
I love those little train tracks! So cute!
Reply
Adorable cake. The decorations look very professional. I’d love to learn how to do it.
Reply
Love it! That is so pretty! Can’t wait to make one for my grand-princess!
Reply
This is a great tutorial! I’ve seen rainbowcakes that have each layer as a different color with kind of thin layers, but I really like the way you did it rings or circles. The cut piece of cake looks really awesome with the colors like that!
Reply
Thank you for teaching me this..I work with children, and I know they would love this as a special birthday surprize!!! You are awesome girl!!
Reply
an explosion of color and a train too what more could a kid want
Reply
You did a great job with this cake, it turn out so adorable. I love the train tracks!
Reply
How adorable is this?! Will be putting this on my ‘to do’ list.
~ Carmen
Reply
Nice job! I have made the tie dye cupcakes, but didn’t think about making a whole rainbow cake like that. Thanks!
Reply
This is beautiful! I was just looking at a cake leveler in Michaels, now I know it’s a good investment!
Reply
What a beautiful cake especially the inside! So cool!
Reply
What a beautiful….tempting and playful cake…
Reply
Great tutorial and such a fun birthday cake!
Reply
What a beautiful and creative cake! I have yet to make a cake like this as there haven’t been any opportunity for it. Thanks for the tutorial. This truly is perfect for children’s cake. I’m sure they love it!
Reply
I think I may be having a blonde moment, so could you explain a little more how you use that cake batter chart? Was curious how you calculate whether you need to double (or reduce) the cake recipe to correlate with the chart.
Love the cake and perfect for a bday party. I’ve seen people do camoflauge cakes before so I assume they use a similar technique and maybe just swirl the colors.
Reply
Michelle on September 18th, 2011 at 3:19 pm
Hi Emily, You need to know how many cups of batter your original recipe makes. For instance, if it makes 4.5 cups and you want to make a 2-layer 8-inch cake recipe, you’d need to double it (you could make cupcakes with the extra).
Reply
Oh, I wish you had posted this last month. I tried making a rainbow cake for my son’s first birthday that involved making like four different cakes and piecing them all together like a puzzle. It was a disaster. This looks so much easier!
Reply
I made a rainbow cake for my daughter 2 years ago for her Birthday. OMG..You would have thought that Justin Bieber was jumping out of the cake when I cut into it!!! The kids went crazy!
Reply
What a great tutorial! Way easier than I imagined it could be =)
Reply
I’m so glad you posted this – now I know what *my* birthday cake will be later this month!
Reply
love it! i will never get over the awesomeness of rainbow cakes… the only annoying part is the clean up, hehe. thank goodness for dish washers is all i can say!
Reply
Does this work with confetti cake?
Reply
Michelle on September 22nd, 2011 at 10:31 pm
Good question, I have never made confetti cake, so I don’t know what is involved??
Reply
This is so awesome! Thank you for sharing – I think I will be making a rainbow cake for my birthday party this weekend!
Reply
This is the 2nd time I’ve heard the name Sutton. It’s the main character of a new ABC Family drama, and that was the first time. I love the name.
Reply
Happy belated birthday to your nephew. Beautiful cake.
Reply
So cool! And it doesn’t seem too difficult to make!
Reply
I am just so impressed by these rainbow cakes. I have seen them a lot lately and I just don’t think I would be good enough to make them. You make it look so easy! I am sure the cake was thoroughly enjoyed!
Reply
Well confetti cake is just a box mix with little sprinkles inside the white cake mix
Reply
Michelle on September 23rd, 2011 at 9:24 am
Ahh, well then yeah sure, I don’t see why not.
Reply
I just saw on good morring America the other day, b-day parties and one had a rainbow cake so i googled how to make a rainbow cake and i came across your page. very cool cake by the way! so my question is what kind of frosting did you use to frost the cake was it store bought or home made? If i was homemade do you mind giving the recipe? =) Thanks!
Reply
Michelle on September 26th, 2011 at 3:56 pm
Hi Jennifer, I use Wilton’s buttercream icing recipe when I do formally decorated cakes since it holds up really well to decorating. Here is the recipe: http://www.wilton.com/recipe/Buttercream-Icing
Reply
Jennifer on September 26th, 2011 at 7:55 pm
Thank’s so much! =)
Reply
Thanks for an incredibly cool tutorial. Smashing cake!
Reply
That is the coolest cake. Looks psychedelic.
Reply
Did you have to double your perfect party cake recipe, or was it enough batter for the two layers?
Reply
Michelle on October 10th, 2011 at 5:45 pm
Hi Jenni, This particular cake was a 10″ round, and I can’t remember if I doubled or tripled the recipe.
Reply
This reminds me a lot of the rainbow ice cream.
Reply
This looks amazing! Never heard of rainbow cake before but will now have to make up a child-related excuse to make it (but it will be just that. an excuse
)
Reply
Hi Michelle
I have made the rainbow cake today and it wasn’t successful. I made it twice but still wasn’t rising at all. It went flat. I followed your recipe and instructIons but not sure why didn’t help. When it says in the instruction, whisk together egg whites and buttermilk, did you mean whisk until light and fluffy or just well blended? Did you make the batter double portion? I also used milk with with 1 tbls of lemon juice and all purpose flour cause I cannot get buttermilk and cake flour here. I lived in middle east.
Please, if you could help me. I will try to make one more time tomorrow. I was very
disappointed as this is a birthday cake for my daughter. Her birthday is this sat.
Thank you for your help.
Best regards
Cassandra
Reply
Michelle on October 20th, 2011 at 3:12 pm
Hi Cassandra, I’m sorry that you had some problems with the cake. The egg and buttermilk only need to be whisked briefly to be combined. Not using cake flour could also have been an issue, since all-purpose flour is significantly heavier.
Reply
I love the idea of this cake
but are the edges always that brownish color?
Reply
Michelle on December 12th, 2011 at 11:17 pm
Hi Jojo, Usually they are just from the baking process and the coloring. However, I find that it never matters because the outside is always covered in frosting and when you cut into the cake all you see are the vibrant colors on the inside!
Reply
You suggested your recipe for “the perfect party cake” for this cake. In that recipe you explained that you put parchment or waxed paper down at the bottom of the pan. In the pictures for the rainbow cake it appears that you did not do that. It looks like you just greased & floured it. Is the parchment/wax paper necessary? Does it help so that the cake doesn’t stick?
Reply
Michelle on February 9th, 2012 at 12:12 pm
Hi Sonia, I do typically use parchment rounds – I find that they help to make sure the cake doesn’t stick. I think I remember running out of parchment for the rainbow cake, so I used a heavy hand greasing and flouring.
Reply
So you only need 1 box of cake mix?
Reply
Michelle on March 12th, 2012 at 1:11 pm
Hi Ashlynn, That would depend on how large of a cake you are making. I think that most cake mixes yield 4.5 cups of batter or so (but I would measure to double check) – I would use that as a starting point and then consult the cake batter chart (link above) to make sure you have enough for the size cake you want.
Reply
I love this cake! I just made it 20 minutes ago. I am so excited to decorate it. I am going to make it look like a girl scout cookie box!
Reply
hi its such a cute cake i have been planing to bake for very long time .. thnks for sharing this great tutorial.. but i wanna sk about the frosting i checked the the frosting u add .. and i dpnt have shorting i mean its not available where i live .. so how can i have white butter cream frosting or do you recommend any other kind of frosting .. we have here cream chantee i am not sure about the splling but its teasty and white but it milts so quiqly and i need to take the cake for a party where is no fridge .. what do u recommend ??
Reply
Michelle on March 31st, 2012 at 10:39 pm
I would recommend this frosting: http://www.browneyedbaker.com/2010/10/28/vanilla-cupcakes-vanilla-buttercream-frosting/. If you can find clear vanilla extract that, use that, otherwise it won’t be perfectly white. But, it will be delicious!
Reply
Hiya, I’m Makeing this cake tomorow for my friends who haven’t tasted this cake since infants/nusary, hope this recipe works for me, if it does I will defiantly recommend you to my friends and family if baking a cake
xx thanks a bunch xx
Reply
Is it possible to use a square pan instead of a round one?
Reply
Michelle on March 31st, 2012 at 11:10 pm
Hi Monique, Yes, you can, but square pans typically hold more batter than round ones. I would consult the cake batter chart (linked to above in the post) to make sure you have enough batter.
Reply
ABSOLUTELY INCREDIBLE!!
EVERY BODY MUST TRY!!!
SO EASY!!!!
Reply
This was extremely helpful!! The step by step instructions for the cake were awesome!! My rainbow cake turned out fabulous:) It was a big hit! So THANK YOU very much!
Reply
So glad I found this! I wanted to make a special dessert for my mom’s birthday (I planned out the dinner and not the dessert!), but didn’t want to go out to the grocery store again. I had a white cake mix on hand, so I made this in cupcakes – 12 regular and 24 mini. I just cut into a mini cupcake and they look awesome! Tomorrow I’ll be frosting them
Reply
hi, what did you put in the middle of the cake? butter icing? or could you put nothing? love this recipe and the cake looks lush!
x
Reply
Michelle on May 24th, 2012 at 12:26 pm
Hi Aimee, Yes, I just put a vanilla buttercream frosting. You could add your favorite filling, as well. I would put at least a very thing layer so the cakes don’t slide off of each other if you stack them and aren’t planning a full filling.
Reply
hi,
is this cake sturdy enough for fondant icing? my son’s birthday is coming up and i would like to try this. thanks so much.
Reply
Michelle on June 4th, 2012 at 10:01 pm
Hi Maria, It all depends on the recipe that you use, as this is merely a tutorial on making the inside colored.
Reply
i really like how u gave details..the cake looks yummy..but i wanted to know if i used the box cake mix how many boxes would i need??? i want to try it for my daughters 2nd b-day
Reply
Michelle on August 3rd, 2012 at 12:16 pm
Hi Marissa, I think most box mixes yield about 4.5 cups of batter. It all depends on the size cake you need – I would use the 4.5 cups as a starting point and consult the cake batter chart linked to in the post and figure out what you need based on the size cake you are baking.
Reply
is’t okay to use a cheesecake pan’s?
or will the batter get through ?
Reply
Michelle on August 9th, 2012 at 5:13 pm
Unless that’s the only pan you have in your kitchen, I wouldn’t use a springform pan; go with a regular cake pan.
Reply
Hi,
Just wondering what was used to make the decorations around the outside of the cake?
Thanks
Reply
Michelle on August 18th, 2012 at 2:59 pm
Hi Emma, I used a star tip for the inside of the diamonds. I don’t remember the exact size now, but it was probably a Wilton #16 or #18.
Reply
Hi Michelle. I just found your blog, and i love it! The rainbow cake looks stunning. Im definitely going to try baking it for my niece’s birthday next week. Wish me luck
Reply
COOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOL!!!!!!!!!!!!!!
Reply
Trying this out as we speak! I’m doing it with a hoe recipe though, so it may not come out as vibrant or fluffy, but hopefully the results will be similarly beautiful and delicious. : ) News on it later!
Reply