The Infamous 'Rainbow Cake' Is Not So Hard After All

There is a cake that has become famous (infamous) on baking blogs and all over the Internet. It's called the "Rainbow cake." It's six layers of rainbow goodness, with each layer representing one color in the rainbow. Roy G Biv would be so excited. Should you ever want to invite him to dinner, be sure to serve this cake.

I have long seen it and wanted to make it since it first appeared on blogger Whisk Kid's blog in 2009. Then she made it with Martha Stewart and the cake exploded on the Internet. It seems like everyone and their mother were talking about it.

I have been wanting to make it for at least two years, but have never had the occasion to do so. Though my husband and I always bake and build cakes from scratch for our children's birthdays, we also usually have very specific requests from our kids. This year we didn't.


I decided my daughter's fifth birthday was the year to attempt this epic monstrosity of a cake. In reading the reviews, I felt pretty nervous about my decision. Each layer has to be baked separately. 

So, first, I separated the batter into six bowls and colored them:

Next I baked each layer separately:

We let them cool completely. Then we froze the individual layers for an hour and brought them out for frosting. We frosted each layer:

Finally, we frosted the cake once and then put it in the fridge. Then we frosted again. See below:

The final product:


Here are some tips if you are going to do this yourself:

  • Triple your recipe: You will use far more cake batter and buttercream than you think. I made both from scratch (this cake has enough that is artificial in it) and I tripled the recipe. We used every last bit of batter and icing.
  • Make a butter cake: This is a bit stiffer than a traditional cake and uses butter over Crisco or vegetable oil, which I prefer.
  • Use gel dyes: This is absolutely crucial. If you use the liquid ones, you will be sorely disappointed in the vibrancy. Additionally, you use far less. I only used about two drops of gel dye, but I would have had to use a whole bottle to achieve these colors with liquid dye. If you really hate food dye, there are natural colors available, though the word on the street is that the colors are dull.
  • Buy disposable pans: You are baking six cakes. Disposable pans, while not environmentally friendly, make the whole experience much more palatable.
  • Use a measuring cup to distribute batter: You want them to be all even, but weighing them out made no sense to me. Just use a measuring cup.
  • Do a crumb layer when frosting: Frost once, then put in the fridge for an hour. Then frost again. It may seem like a silly, small thing, but it makes a big difference in the final product.
  • Freeze the individual cakes: This helps avoid crumbs when frosting.
  • Use cake release: This costs a little more than just butter and flour, but it's worth every penny. It turns out PERFECT cakes with no cracking.

Would you ever attempt the Rainbow Cake?


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