apple sauce (use 1/3 cup per box of mix in place of cooking oil)
food coloring (i used a box of assorted colors for the cake and neon colors for the frosting)
Mix one box of cake mix as directed on the box, substituting the applesauce in place of the cooking oil.
Preheat oven and prepare pan. I have a set of the rubberized cake pans, this is a deep 9 1/2 round cake pan that worked very well for the entire box of cake mix.
Separate batter into 6 bowls, increasing the amount in each bowl. Example, I put 2 spoonfuls in the first bowl for purple, 3 spoonfuls int he second for blue, 4 for green, etc.
Mix each bowl with food coloring until desired color.
Start with your outside color (red in my cake)and pour the entire amount in the center of the pan. Let it flatten out as much as possible on it's own.
Continue with each consecutive color, making sure you pour into the center of the pan. Each color with push the previous colors further out to the edge.
Bake as directed on box. Mine took about 38 minutes per layer.
While the first layer is baking, start mixing, separating, and coloring the second layer.
Let both layers cool completely (I let them sit overnight).
Separate and color frosting in the same manner as the batter, except the two colors for the center of the cake will take more than the outer colors. This is where the extra tub of frosting was useful.
I started the frosting in the center with the green and yellow and worked my way out to purple and red.