From The Best Bake Sale Ever Cookbook. Good topper for these chocolate cupcakes.
1/2 cup plus 2 T butter, room temp
4 cups confectioners sugar
2 ounces unsweetend chocolate, melted and cooled
1/4 t salt
3-4 T half and half, heavy cream, or buttermilk
1 t vanilla
With an electric mixer, cream the butter until light. Add the sugar, chocolate, salt, and 3 T buttermilk, and blend until smooth. Blend in the vanilla.