2/3 c. butter
1 c. firmly packed brown sugar
1/3 c. milk
3 c. confectioners sugar

Melt butter in saucepan. Add brown sugar and cook over low heat for 2 minutes, stirring constantly. Add milk and cook until mixture comes to a boil. Remove from heat and cool about 10 minutes. Gradually add powdered sugar until frosting is of spreading consistency, beating well after each addition.