1 cup butter
2 cups firmly packed brown sugar
1/4 cup + 2 tbsp whipping cream
2 tsp vanilla
3 3/4 cups confectioners' sugar
In a 3-quart saucepan over medium heat, melt the butter; add the brown sugar. Bring the mixture to a boil while stirring constantly. Stir in the cream and the vanilla; return to a boil. Remove the pan from the heat and allow to cool for an hour.
Transfer the caramel mixture from the saucepan to a mixer bowl. Sift the powdered sugar into the caramel mixture and beat on high speed until creamy and of a spreading consistency.
Yield: Almost 4 cups; enough to fill and frost a 4-layer cake.