1Heat oven to 350°F. Generously spray four 8- or 9-inch round cake pans with baking spray with flour. Make cake batter as directed on boxes. Pour batter into pans.
2Bake as directed on box for 8- or 9-inch rounds. Cool 10 minutes; remove from pans to cooling racks. Cool completely, about 30 minutes.
3Meanwhile, divide frosting among bowls, and tint with food color as desired. You will need about half a container of frosting for between each of the layers and one and a half for the outside and top of the cake. Set the one and a half containers aside if you want to keep it white for the outside and top. Use whatever colors you desire for the 3 bowls of frosting for between the layers.
4Spread 1 tablespoon frosting on cake plate to act as glue. Place 1 cake layer on plate. Spread with half container of frosting. Repeat twice. Top with last layer. Frost outside and top of cake completely with the one and a half containers frosting. Immediately cover cake with sprinkles.