FROSTING
1 cup confectioner's sugar
2 ounces cream cheese -- softened
2 tablespoons cocoa
1 tablespoon milk

In a small bowl, stir peanut butter and confectioners' sugar until smooth. Chill 15 minutes. Meanwhile in a large bowl beat sugars, butter and cream cheese until light and fluffy.
Add vanilla and egg. Combine flour, cocoa and baking powder; add to cream cheese mixture and mix well. Roll into 1 inch balls. Place half of the balls 2 inches apart on a greased baking sheet. Make a depression in the center of each ball with your thumb; fill with 1 teaspoon of chilled peanut butter mixture. Flatten remaining balls and place on top, pressing edges to seal.
Bake at 350 for 8 to 10 minutes. Remove to a wire rack to cool.