1/2 cup butter or margarine
1 cup dark brown sugar
1/4 teaspoon salt
1/4 cup milk
2 cups confectioners sugar

1) Melt 1/2 cup butter or margarine in saucepan over low heat.  

2) Stir in 1 cup dark brown sugar, firmly packed, and 1/4 teaspoon 
salt.  

3) Bring to a boil over medium heat; boil hard for 2 minutes, 
stirring constantly.  

4) Remove from heat.  Stir in 1/4 cup milk.  Return pan to heat and 
bring to a full boil.  Remove from heat, cool to lukewarm.  

5) Stir in 2 cups confectioners sugar and beat until smooth.  If 
frosting is too thick, beat in a little milk.