Whoopie Pies

½ cup (1 stick) butter, softened

1 cup firmly packed brown sugar

1 egg

1 teaspoon vanilla extract

2 cups all-purpose flour

cup cocoa powder

1 teaspoon baking powder

1 teaspoon baking soda

frac12; teaspoon salt

1 cup buttermilk

Filling

6 tablespoons butter, softened

1frac12; cups confectioners' sugar, sifted

teaspoon salt

1 jar marshmallow creme (about 7 ounces)

1 teaspoon vanilla extract

Heat oven to 350 degrees. Lightly spray Whoopie Pie Pan with nonstick cooking spray.