1. Preheat oven to 375degrees F. Line baking sheets with parchment; set aside. In medium bowl combine flour, cocoa powder, baking soda, and salt; set aside.

2. In large mixing bowl beat butter on medium to high 30 seconds. Beat in brown sugar until light and fluffy. Beat in egg and vanilla. Alternately add flour mixture and buttermilk, beating after each addition just until combined. Stir in food coloring.

3. Spoon batter in 1-or 2-inch diameter rounds, about 1/2 inch high on prepared baking sheets, allowing 1 inch between each mound.

4. Bake 7 to 9 minutes for 1 inch cookies or 9 to 11 minutes for 2-inch cookies, or until tops are set. Cool completely on baking sheet on rack. Remove cooled cookies from baking sheets.

5. To fill, spoon Whoopie Pie Filling on flat sides of half the cookies. Top with remaining cookies, flat sides down. Makes 60 one-inch or 42 two-inch cookies.

WHOOPIE PIE FILLING:
In medium mixing bowl, beat butter and cream cheese until smooth. Fold in marshmallow cream.

To store: Refrigerate in air tight container up to 4 days. Let stand at room temperature 15 minutes before serving.