1/2 c. butter
1 c. light brown sugar
1/2 c. evaporated milk
2 to 2 1/2 c. confectioners sugar
1 tsp. vanilla or maple extract

Melt butter over low heat. Remove from heat. Add brown sugar, stirring until smooth. Over low heat, bring to boil, stirring. Boil 1 minute. Remove from heat. Add milk. Over low heat, return to just boiling. Remove from heat; let cool until bottom of pan is lukewarm. With mixer, beat in confectioners' sugar until mixture is thick. Add confectioners' sugar as needed to spreading consistency. Add vanilla.