1 box white or yellow cake mix
Ready-made white or vanilla frosting
Make the cake according to the package instructions. Pour the batter into whatever size cake pan(s) that you want. Scatter drops of different food colors over the top of the batter. Use a butter knife to cut through the batter using a swirling motion. This will blend in and mix up the colors. Bake the cake and cool.
Frost with white frosting. Scatter dots of food coloring over the frosting. Then use a wooden pick and swirl the colors into the frosting.