Chocolate Icing:

2 c. sugar
1/2 c. milk
1 stick butter
3 tbsp. cocoa
1/2 tsp. vinegar (vinegar will keep sugar from crystallizing)

Mix together and bring to a boil. Cook 1 minute. Add teaspoon vanilla extract. Ice each layer of cake.

Layers:

1 box Duncan Hines yellow cake mix

Mix as directed on box. Add different cake coloring to each layer. Can use 2 layers of green, red, chocolate and leave one plain as long as you alternate layers. Pour thin layers of batter onto 8-inch skillet, about enough to cover bottom of pan and bake in 500°F to 550°F oven for about 2 1/2 to 3 minutes per layer. Spray skillet with nonstick spray each time. An 8-inch cake pan may be used to cook layers.