1/3 c. butter, melted
1 c. light brown sugar, firmly packed
2 1/2 c. confectioners sugar
1/4 c. milk

Combine melted butter and brown sugar. Add confectioners sugar (sifted if lumpy) alternately with the milk. Beat until smooth. If frosting is too thick to spread easily, beat in 1/2 teaspoon milk at a time.