Chocolate Frosting

Directions

1. 1
   Combine first 4 ingredients in a heavy saucepan.
2. 2
   Cook over low heat until chocolate and butter melt, stirring constantly. Cook over medium heat, stirring constantly, until mixture boils. Boil 1 minute, stirring constantly.
3. 3
   Remove from heat; stir in vanilla.
4. 4
   Beat at high speed of an electric mixer until of spreading consistency.
5. 5
   Immediately spread on cake.
6. 6
   Yield: enough for one 3-layer cake.