Buttermilk Brownie Icing
Enough to cover a 13 x 9-inch pan of brownies
1/3 cup butter or margarine
1/4 cup buttermilk
1/3 cup unsweetened cocoa powder
1/4 cup confectioners' (powdered) sugar
In a medium saucepan, melt butter over medium heat. Add buttermilk and cocoa. Bring to a boil, whisking until smooth. Remove from heat and whisk in powdered sugar until no lumps remain. Pour icing over brownies. Spread evenly with a metal spatula. Chill for at least 2 hours or until icing is set.