When my friend Julie asked me if I would help her make this cake for her daughter’s fifth birthday (aka make the cake for her while we talk and drink martinis, she clarified), I couldn’t say no.
I was asked how long it took me to make this cake. The truth is, the cake making part is the easy/quick part. It’s the decorating I chose for the cake that took me a long time. The cake recipe I used goes together in a snap. The most time-consuming part is divvying up the batter into bowls to mix with food coloring – Julie helped me with this part!
Though this cake looks intimidating, it’s really not that difficult to make – especially if you’re going low maintenance with the decorations. Obviously the cake was a huge hit at the party. To date, this is the most impressive cake I’ve made.
- Moist White Cake (double recipe)
- Lemony Swiss Meringue Buttercream
- Rainbow colored decorations and/or candy
- Preheat oven to 350 degrees. Grease six 8-inch-round cake pans (or as many 8-inch cake pans as you have, reusing them as necessary) with shortening, cover the bottom with wax paper or parchment paper, grease again and then flour (be sure to shake any remaining amounts of flour from the pans).
- Divide batter evenly between six medium bowls. Add enough of each color of food coloring to each bowl (I used Wilton gel food coloring), whisking, until desired shade is reached. Transfer each color to an individual cake pan. Transfer to oven and bake until a cake tester inserted into the center of each cake comes out clean, about 20 to 22 minutes (working in batches if necessary).
- Remove cakes from oven and transfer to a wire rack; let cool for 10 minutes. Invert cakes onto a wire rack; re-invert and let cool completely. Freeze until ready to assemble the cake.
- Using a serrated knife, trim tops of cakes to make level. Place four strips of parchment paper around perimeter of a serving plate or lazy Susan. Place the purple layer on the cake plate. Spread a scant 1 cup buttercream filling over the first layer with a small offset spatula so it extends just beyond edges. Repeat process with blue, green, yellow, and orange layers. Place the remaining red layer on top, bottom-side up.
- Gently sweep away any loose crumbs with a pastry brush. Using an offset spatula, cover the top and sides with a thin layer of frosting (also use any of the excess frosting visible between the layers). Refrigerate until set, about 30 minutes.
- Using an offset spatula, cover cake again with remaining frosting.
- Decorate with any rainbow decorations available, such as Chocolate Bark Cake Garnish, sprinkles (or jimmies – if you live in the Midwest), rainbow-colored Lollipops, etc.