1. Combine cocoa, milk and butter in a medium-sized, heat- resistant, non-metallic bowl. 2. Heat, uncovered, in Microwave Oven 1 1/2 minutes or until butter is melted. 3. Gradually add confectioners' sugar and beat with electric mixer till smooth. Stir in vanilla. Fills and frosts two 8-inch layers. Note: If consistency is too thick, add 1 to 2 tablespoons more milk as you are beating in confectioners' sugar.
