Jill Takes The Cake: Navneet's Rainbow Birthday Cake

As you may know, I like to bake for the people in my group at work on their birthdays. Navneet wanted something vanilla. "Whatever inspires you," he told me. It didn't take long to find inspiration. I have adapted this recipe from Cupcake Addiction.

Ingredients:
3 Pillsbury Moist Supreme white cake box mixes (1 1/2 boxes per batch)
12 egg whites (6 per batch)
1 1/2 cups vegetable oil (3/4 cups per batch)
3 1/2 cups water (1 7/8 cups per batch)
Food coloring
Triple batch of icing found here

Equipment:
Mixer
Spatula
3-8 inch cake pans (greased and floured)
Cake leveler, or a serrated knife if you cut level
5 inch diameter cookie cutter (I made one from flexible metal I bought at Lowes but you can cut a large can of Quaker Oats to make one or even use a 3D printer.)
2 1/2 inch diameter cookie cutter

To make this cake you will need to divide one of the cake mixes in half. So pour one into a bowl and whisk it so that it is mixed well, then divide it best you can in half. Use a small scale if you have one. The first set of 3 layers I made was red/orange/yellow, and the second set was blue/green/purple.

1) First mix up the batter according to the directions on the box, adjusted for 1 1/2 mixes.

Rough calculations for 1 1/2 cake mixes.

Pillsbury brand worked well.

2) Pour the batter into 3 bowls. Add food coloring and mix well. Pour each color into a cake pan and bake for 18-20 minutes.

3) Remove from cake pans after 10 minutes and allow to cool on racks until completely cool to the touch.

4) Level with a cake leveler or a knife if you have a steady hand. I can't cut straight but I love my $3.50 cake leveler from Hobby Lobby. Using your cutters, cut each of the 3 layers like this.

5) Ice the inner walls of the two donut shaped parts, then mix them up like this. The icing will glue them together. Wrap them up in plastic wrap and place in the refrigerator for 30 minutes.

6) Stack layers putting a small layer of icing in between. Wrap in plastic wrap and place in the refrigerator again.

7) Trim off a very small bit of the sides with a serrated knife. This makes a huge difference in how easy it is to ice. Crumb coat, final coat, and decorate refrigerating as you go. A cake this big needs the support of being chilled. Remove it from the refrigerator a couple of hours before serving.