- 1/3 cup (packed) golden brown sugar
- 4 tablespoons dark rum
- 1 tablespoon grated tangerine or orange peel
- 1 cup (2 sticks) unsalted butter, room temperature
- 1/2 cup powdered sugar
- Stir brown sugar and 3 tablespoons rum in heavy small saucepan over medium-low heat until sugar dissolves. Mix in tangerine peel. Cool to room temperature.
- Using electric mixer, beat butter in medium bowl until light. Add remaining 1 tablespoon rum, brown sugar mixture and powdered sugar and beat until well blended and smooth. (Can be prepared 1 week ahead. Cover and refrigerate. Bring to room temperature before serving.)