I had come across a rainbow cake a few times while browsing cake ideas online. It is so pretty and festive and I had been so eager to try it. But I didn’t want to make a 6 layer cake just to take pictures and blog about it. I wanted to make it for a special occasion. And my friend was coming in town for her 30Th birthday, and what is more special then that? And I knew she would appreciate it.
Because of a suggestion from my artistic husband, I decided not to layer the cake in the traditional ‘rainbow’ order. I used all the same colors, just in a random order. I sort of liked it better that way :)
The cake looks much more difficult then it actually is. Especially the way I make it, it is extremely easy, but so impressive!

Cake
2 boxes white cake mix
1 cup applesauce
6 eggs
2 1/2 cups water
4 tbsp vanilla extract
Food coloring: red, orange, yellow, green, blue, purple

Frosting
2 sticks unsalted butter, softened
2 tbsp vanilla extract
8-9 cups confectioners’ sugar, sifted
1/2 -1 cup milk, may need more if frosting is too thick

Cream the butter in the bowl of an electric mixer until light and fluffy. Beat in the vanilla extract. With the mixer on low, add the confectioners’ sugar, scraping down the bowl halfway through. Add the milk, and the rest of the sugar, and continue to beat until you’ve reached your desired consistency. Be sure not to whip too long, or the frosting may begin to separate.

Preheat oven to 350
Mix all cake ingredients in a big bowl. Mix only until Incorporated. Divide the cake mix into 6 smaller bowls. Mix the food coloring into the bowls. Again, mix only until Incorporated.
* use liquid food coloring rather then the gel. The gel requires more mixing, and the more mixing you do to the batter, the flatter the cake will be. And you don’t want that.
Grease 6 cake pans. If you only have a few cake pans, just bake them in shifts. Pour 1 color into 1 cake pan and bake for 18 – 22 minutes. Until a knife inserted comes out clean. Repeat with each of the 6 colors.
Allow to cool for about 5 minutes before removing the cake from the pan. Then cool completely on a wire rack.
Using a large serrated knife, shave off the rounded top of the cake. So you have a flat disc that will lay even on top of each layer and not puff up in the middle.

Put about 3 tbsp of frosting on top of each layer of cake.
And then spread the rest of the frosting around the sides of the cake and on the top.
Decorate the cake however you want, with sprinkles or colored sugar, or whatever.