How to Make a Rainbow Cake

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 πŸ˜‰

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 ΒΎ-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 ΒΎ-inch wide. From there, I cut across the strip in ΒΌ-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!


110 Responses to “How to Make a Rainbow Cake”

Comment Pages 1 2
  1. Jessica on September 14, 2011 at 12:47 am

    Such an adorable birthday cake! I really love all the colors in rainbow cakes…I just need to break down and make one! πŸ˜€


  2. Rashmi on September 14, 2011 at 1:53 am

    Wow – that is such a beautiful cake! Love it!


  3. katie on September 14, 2011 at 1:56 am

    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


  4. CouponClippingCook on September 14, 2011 at 3:30 am

    This is such a cool recipe. It looks so fun and delicious too! Love the colors!


  5. misbah on September 14, 2011 at 4:05 am

    Such a adorble cake. :)


  6. Rosie on September 14, 2011 at 4:13 am

    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


  7. Kathryn on September 14, 2011 at 4:56 am

    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 πŸ˜‰


  8. Sandra K on September 14, 2011 at 5:52 am

    I love the rings of colours. Thank you!


  9. Katrina on September 14, 2011 at 6:31 am

    I’ve wanted to make one of these for a while! They look so yummy!


  10. Kerry on September 14, 2011 at 7:40 am

    Fabulous, this is definitely on my to bake list – thanks for the tutorial!


  11. Liz @ Microwave Goddess on September 14, 2011 at 8:42 am

    Gorgeous! Can’t wait to try this!


  12. Leah from Sweet and Sour Showers on September 14, 2011 at 8:49 am

    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?


    • Michelle on September 18th, 2011 at 3:04 pm

      Yes, absolutely!


  13. Dawn on September 14, 2011 at 9:47 am

    Can you do this for cupcakes? If so how many would you get?


  14. Ally on September 14, 2011 at 10:30 am

    I’ve always been fascinated by rainbow cakes! This recipe makes them feel achievable! Thanks.


  15. Bianca on September 14, 2011 at 11:10 am

    This is so awesome! I made rainbow cupcakes a little while ago the same way :) Love your blog!


  16. Rachel @ The Avid Appetite on September 14, 2011 at 11:18 am

    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!


  17. jayme @ No Regrets Living on September 14, 2011 at 11:20 am

    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!


  18. natalie (the sweets life) on September 14, 2011 at 12:16 pm

    you’re an old pro!! this looks amazing!


  19. Jo Green on September 14, 2011 at 12:36 pm

    Wow, this is beautiful. The colors are so vibrant! Now I am craving some cake. :)


  20. Ali @ Gimme Some Oven on September 14, 2011 at 1:35 pm

    Incredible!!! I’ve been wanting to try this. Thanks for the detailed tutorial! :)


  21. Caitlin @ Cake with Love on September 14, 2011 at 2:01 pm

    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!


  22. Paula on September 14, 2011 at 2:44 pm

    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.


  23. Lindsay @Eat, Knit, Grow on September 14, 2011 at 3:00 pm

    So pretty! Is there something around the purple? Or is that just crusty part from baking?


    • 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.


    • Michelle on September 18th, 2011 at 3:12 pm

      Just the crusty part from baking.


  24. Kerry on September 14, 2011 at 3:20 pm

    What a pretty cake! I think everyone needs a rainbow cake in their life.


  25. Lauren from Lauren's Latest on September 14, 2011 at 4:43 pm

    I love those little train tracks! So cute!


  26. Annamraria A on September 14, 2011 at 4:46 pm

    Adorable cake. The decorations look very professional. I’d love to learn how to do it.


  27. Kristy on September 14, 2011 at 4:49 pm

    Love it! That is so pretty! Can’t wait to make one for my grand-princess!


  28. Elizabeth Branch on September 14, 2011 at 4:49 pm

    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! :)


  29. Erika Hollis on September 14, 2011 at 4:51 pm

    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!!


  30. tom (watkins products associate) on September 14, 2011 at 4:55 pm

    an explosion of color and a train too what more could a kid want


  31. Kathia on September 14, 2011 at 4:58 pm

    You did a great job with this cake, it turn out so adorable. I love the train tracks!


  32. Baking is my Zen on September 14, 2011 at 5:08 pm

    How adorable is this?! Will be putting this on my ‘to do’ list.

    ~ Carmen


  33. Chaos Mommy on September 14, 2011 at 5:18 pm

    Nice job! I have made the tie dye cupcakes, but didn’t think about making a whole rainbow cake like that. Thanks!


  34. Jen @ Savory Simple on September 14, 2011 at 5:45 pm

    This is beautiful! I was just looking at a cake leveler in Michaels, now I know it’s a good investment!


  35. Happy When Not Hungry on September 14, 2011 at 6:34 pm

    What a beautiful cake especially the inside! So cool!


  36. Priyanka on September 14, 2011 at 8:12 pm

    What a beautiful….tempting and playful cake…


  37. Lauren at Keep It Sweet on September 15, 2011 at 6:53 am

    Great tutorial and such a fun birthday cake!


  38. Amy @ Gastronome Tart on September 15, 2011 at 7:49 am

    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!


  39. Emily on September 15, 2011 at 1:52 pm

    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.


    • 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).


  40. Lisa @ The Cooking Bride on September 15, 2011 at 2:13 pm

    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!


  41. leslie on September 15, 2011 at 9:32 pm

    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!


  42. Peggy on September 16, 2011 at 7:49 am

    What a great tutorial! Way easier than I imagined it could be =)


  43. Valerie on September 16, 2011 at 10:34 pm

    I’m so glad you posted this – now I know what *my* birthday cake will be later this month! πŸ˜‰


  44. Christine on September 17, 2011 at 10:21 am

    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! :)


  45. 13YearOldBaker on September 18, 2011 at 2:32 am

    Does this work with confetti cake?


    • 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??


  46. Ally on September 18, 2011 at 12:49 pm

    This is so awesome! Thank you for sharing – I think I will be making a rainbow cake for my birthday party this weekend!


  47. Kelsey on September 20, 2011 at 10:37 am

    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.


  48. Christine on September 20, 2011 at 6:06 pm

    Happy belated birthday to your nephew. Beautiful cake.


  49. Stephanie @ Eat. Drink. Love. on September 20, 2011 at 7:05 pm

    So cool! And it doesn’t seem too difficult to make!


  50. RavieNomNoms on September 21, 2011 at 1:32 pm

    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!


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