3 tbsp. butter
2 tbsp. cocoa
1 1/2 c. confectioners' sugar
2 tbsp. milk
1 tsp. vanilla

Melt butter in a medium saucepan. Stir in cocoa until dissolved. Add confectioners' sugar, milk and vanilla. Stir until smooth. Add more milk if necessary to soften consistency. Excellent frosting for marbled brownies.