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

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