1/3 c. butter, softened
2 oz. unsweetened melted chocolate (cool)
1 1/2 tsp. vanilla
About 2 tbsp. milk

Mix butter and chocolate. Stir in 2 1/2 cups powdered sugar. Beat in vanilla and milk until frosting is of spreading consistency. Fills and frosts two 8 or 9-inch layers or frosts a 13x9-inch cake.