This is one of my favorite chocolate frosting recipes.
Chocolate Frosting IV
3 cups white sugar
6 tablespoons unsweetened cocoa powder
1/4 cup water
1 1/2 cups evaporated milk
1/2 cup butter
1 In a saucepan, combine sugar and cocoa. Stir in water to make a paste. Add milk and butter. Cook over medium heat until it comes to a boil. Continue boiling for 5 minutes. Remove from heat and beat until cool enough to spread on cake.