Makes about 3 cups.

INGREDIENTS

  • 1/2 cup (1 stick) unsalted butter
  • 2 ounces unsweetened chocolate, chopped
  • 1/3 cup unsweetened cocoa powder
  • 2 teaspoons vanilla
  • 2 cups powdered sugar
  • 2/3 cup (about) sour cream

    DIRECTIONS

    Melt unsalted butter and chocolate in heavy small saucepan over low heat, stirring constantly until smooth. Transfer to large bowl. Whisk in cocoa powder and vanilla. Whisk in 1 cup sugar and 1/3 cup sour cream. Whisk in remaining 1 cup sugar. Gradually whisk in enough of remaining sour cream to form spreadable frosting.