{recipe + how to} Super Tall Amazing Rainbow Birthday Cake!

Note: this was the most-searched recipe on my previous blog, so I’m re-posting it here. It’s one of my earliest blog entries–from about 3 years ago–so the pictures are a little less polished than usual! They actually look like they were taken with Hipstamatic, which wasn’t invented yet, which is kind of weird. The cake is still a hit, though. -KM

When my older sister was about 9, my mom made her this legendary multi-tiered cake that was all white on the outside but with each layer of the cake being a different color of the rainbow, arranged, natch, in rainbow order. I re-created a similar cake about 4 years ago when my niece Leila turned 5, with a chocolate outside and a strong structural resemblance to the leaning tower of Pisa. Yesterday my other niece Mitra turned 5, and got her very own rainbow cake, thanks to the combined efforts of my sister and I.

The kids go CRAZY when you cut into it- but believe me, it’s not easy to cut into it. The cake comes out super tall and huge, so much so that out of 6 or 7 kids yesterday, only 1 ate the whole piece (but I’m not naming names. *cough* Nico *cough*.)

So how do you make this beaut? It’s actually not as hard as it looks. We just use 2 yellow cake mixes (the yellow cake mix renders richer colors than the white.) Mix the cake mixes as usual, divide the whole lot evenly among 6 bowls and use regular food color to get the different colors. (Birthday girl Mitra was the colorizer for this particular cake and I think she did a fine job of getting the job done.)  Bake each layer separately, cool, then stack, gluing together each layer with a bit of icing. There is actually a fair amount of icing between each layer, but it gets smooshed down by the sheer weight of the thing. Ice the entire outside and decorate with candles and/or sprinkles. If it starts tipping over or seeming teetery, stick some wooden skewers in it in a couple of places and take them out right before cutting. Voila! Rainbow cake! A mid-icing shot:

The icing our mom used so many years ago and that we used yesterday is a version of that fluffy marshmallowy meringue-y 7-minute icing. You can use any icing but this one sets up a bit and adds some structural integrity- as long as it’s not out too long. You should definitely ice this puppy the same day as the party if you use this type of icing. Here is the easy shortcut recipe in the appropriate amount to easily cover and fill this giant monstrosity.

No-Boil 7-Minute Icing


  • 6 egg whites
  • 1 1/2 cup sugar
  • 1-2 tsp vanilla extract
  • 1/2 tsp cream of tartar
  • 1/2 cup boiling water


  • In the bowl of a Kitchen-Aid, combine everything except boiling water with the whisk attachment.
  • While whisking, slowly pour in boiling water.
  • Beat about 7 minutes, until mixture holds stiff peaks.
  • Use immediately or texture will become weird and won’t spread easily.

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8 Responses

  1. Dana says:

    No wonder that cake is a hit! The texture of the icing looks very alluring besides the rainbow of color.

  2. Martha says:

    I’m gonna try the rainbow cake this weekend for Mia’s birthday. Wish me luck! I hear it’s best to use the professional food coloring to get good vivid colors? That’s really the whole objective with this baby so I think I will try to find them.

    • Karen says:

      @Martha – I have used the liquid food coloring too (I think that’s what I used for this one) – just use kind of a lot so the batter is pretty bright.

  3. Kevin says:

    Wow. Loved this cake. I made it for a family reunion and it helped me come out to my entire family all at one time. 🙂

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