1/2 c. butter
1/4 c. milk
1 c. packed brown sugar
3 c. confectionery sugar

In a medium saucepan melt butter; stir in brown sugar. Cook and stir until bubbly. Remove from heat. Add milk; beat vigorously until smooth. By hand, beat in enough of the powdered sugar to make of spreading consistency. Quickly frost the top of one 13x9 inch cake or tops of two 8 inch or 9 inch layers.