Caramel Frosting
["1 1/2 c. brown sugar", "1 1/2 c. white sugar", "1 1/2 c. milk", "2 Tbsp. butter"]
["Combine sugar and milk and bring to a boil, stirring constantly, then cook without stirring to soft ball stage, about 232\u00b0 on candy thermometer.", "Remove from heat.", "Add butter and cool to lukewarm.", "Beat until thick and creamy."]
["brown sugar", "white sugar", "milk", "butter"]