6 Layer Rainbow Cake

My baby girl is 3! As per tradition, Anya got to pick out her birthday meal. She picked pink pizza and rainbow cake… just unique enough that I had to think about how to make it work.
I had seen a beautiful, layered cake on Food Gawker and was in love. Each layer was a different colour with white icing between each layer. I separated and coloured 2 boxes of white cake mix. Since I only own 2 round cake pans, I had to bake 2 layers at a time. Technically, a rainbow has 7 colours (ROYGBIV- red, orange, yellow, green, blue, indigo, and violet) but I decided that purple is purple…I only need 1 purple layer. We bought a big bag of M&Ms to decorate the top of the cake and I think it turned out great!
But the best part of the whole cake was when we cut into it. The kids were amazed by how colourful it was inside and we had a very happy birthday girl. 
6 Layer Rainbow Cake

Ingredients

2 boxes white cake mix (mixed according to package directions)
Wilton icing colours (red, orange, yellow, green, blue, purple)
1 pound unsalted butter, room temperature
1 pound vegetable shortening
8-10 cups icing sugar
Directions

Preheat oven to 350°. Mix both boxes of cake mix according to package directions. Separate the cake batter into 6 bowls and tint each bowl a different colour. The batter should be a deep colour. Line 9 inch round cake pans with foil and then spray with cooking spray. Bake for 20-25 minutes, until a toothpick inserted into the center of the pan comes out clean. Cool each layer for 5 minutes and remove from pan to a cooling rack. 
Meanwhile, prepare icing. Beat unsalted butter and vegetable shortening on high until smooth and completely blended. 1 cup at a time, add icing sugar and mix well between each addition. Continue to add icing sugar until it reaches a good consistency; not too runny, not too thick. Add more icing sugar if necessary or a bit of milk if it becomes too thick. Set aside.
When all layers are completely cool, cut the rounded top off to create a level cake. Starting with the red layer, begin stacking the layers (adding about 1/2 a cup of icing between each layer). Spread the icing evenly to the edge of the cake. Continue to stack the layers (orange, yellow, green, blue, purple). Spread the remaining icing over the top and sides of the cake, covering well. 

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15 Responses to 6 Layer Rainbow Cake

  1. Aww! Happy birthday Anya! My baby brother is 3 and totally rocks it in the kitchen.. he's quite bossy about what we're going to make. This cake is absolutely adorable and I totally dig the rainbow.

  2. This is super fun and super pretty. I'll have to keep this in mind for one of my kids' birthdays.

  3. Nisa Homey says:

    Happy b'day princess….beautiful cake…bookmarked!!

  4. Swee San says:

    wow so colourful and pretty! It's going to take me alot of courage such a colourful cake!

  5. That is a pretty amazing looking cake. How did you manage the pink pizza?

  6. Barbara says:

    I'm going to try this for my kids… they would be so excited to cut into this cake and find such a surprise!

  7. Anonymous says:

    I was wondering about the pink pizza too! The cake is gorgeous!

  8. Anonymous says:

    Luckily you were right about having 6 colors in the rainbow. I'm a high school science teacher and about 3 years ago, it was officially decided Newton's idea about "indigo" being an official color on its own was incorrect. It is just a shade of violet and because the other colors aren't differentiated by shade (ie. there's no light green and dark green). Look at you smartie pants! Just as you thought, purple is purple! (And ROYGBIV is no longer taught in textbooks. haha. Its now just ROYGBV)

  9. BigBearswife says:

    I love rainbow cakes! I have been meaning to make one for almost every holiday and never do… maybe I will make one for easter! Yours turned out great!

  10. busycooking says:

    Impressive! I just tried doing cupcakes with M&Ms on top but they all melted off and looked really messy. Did you have this problem? Maybe it was because my frosting was chocolate mousse and milk based?

  11. Tara says:

    The frosting was quite thick so the M&Ms stayed put. As for the pink pizza, I replaced the water in a pizza dough recipe with canned beet juice! It worked out VERY well!

  12. Jenn says:

    Anya is so cute!! Your cake turned out perfect.

  13. icelaine says:

    im trying out the recipe now! (so far all well) altho for for a gay wedding, not a kids bday party ;)

  14. Roshini says:

    About how many drops of food coloring should I use? Also how much batter did you use for each layer? Thank you!

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