1/2 c. (1 stick) butter
1 c. dark brown sugar
1/4 tsp. salt
6 tbsp. milk
3 c. powdered sugar

Melt butter in 2 quart saucepan. Stir in brown sugar and salt. Bring to a boil and boil hard for 2 minutes, stirring constantly. Remove from heat and add milk stirring vigorously. Put back over heat and bring to a full boil again. Set aside to cool, about 20 minutes, until lukewarm. Stir in powdered sugar and beat until smooth and cool enough to spread.