A 7-layered 6-inch round cake in colors of the rainbow, with white vanilla frosting. Regular white cake recipe found on the web, with food colors - the fun was in mixing the 4 colors (red, blue, green yellow) plus a smidgen of black to make gorgeous VIBGYOR.
Each 6-inch round layer was about an inch thick. I baked them in batches and assembled them the night before her birthday.
I did think of making a single layer cake with rainbow rings or something, but the night before the big day I went with what I know works - layering. No psychedelic 70s style cake this time.
Nothing very innovative about this recipe, but this is exactly what my little girl wanted for her birthday and I was happy to make it for her.
Marthastewart.com has a rainbow cake recipe which was the inspiration for this, but, rather than red on top, I stacked them with violet at the top as it seemed prettier than the other way. Totally subjective, of course...
After the Penguin cake for the little guy's birthday, this was so much easier: a large batch of cake batter (7 cups), 6-inch round cake tin (I had multiples so I could bake a few at a time), red, blue, yellow, green food colors, some simple vanilla buttercream frosting, rainbow sprinkles; the wait for the cake to cool so I can frost them was the toughest part.
Of course, I had enough trimmings when I flattened the tops of the cakes to layer them to make cake pops. And knowing that there were Penguin cake pops for her brother's birthday, she was naturally expecting some "surprise" cake pops, and she wasn't disappointed.