Boiled Chocolate Icing

Directions

1. 1
   Put sugar, milk and cocoa in a heavy saucepan.
2. 2
   Cook and stir until mixture cannot be stirred down.
3. 3
   Put lid on; cook 1 minute over medium heat.
4. 4
   Remove and add 1 stick butter and 1 teaspoon vanilla.
5. 5
   Stir.
6. 6
   Frost cake.