1/2 c. butter
1 c. firmly packed brown sugar
1/4 tsp. salt
2 1/2 c. confectioners sugar
1/2 tsp. vanilla

Melt butter in a large saucepan. Blend in brown sugar and salt. Cook over low heat for 2 minutes, stirring until mixture comes to a boil. Remove from heat. Blend in confectioners sugar gradually. Add vanilla. Mix well. Thin with a few drops of cream, if needed.