S'More Whoopie Pies

Preheat oven to 375u0b0F.
1.) Blend butter and marshmallow creme together until smooth. Slowly add powdered sugar, blend until creamy.
2.) In a large bowl, beat the butter and sugar for a minute or so, until well combined. It will have the consistency of wet sand. Add the egg and vanilla and beat until smooth.
3.) In a medium bowl, stir together the flour, cocoa and salt. In a small bowl, stir the baking soda into 1/2 cup very hot water until dissolved.
4.) With the mixer on low or stirring by hand, add about a third of the dry ingredients, then half the buttermilk and half the baking soda mixture, mixing each time just until blended. Repeat with another third of the dry ingredients, the rest of the buttermilk and baking soda mixture, and then the rest of the dry ingredients, mixing each time just until combined.
5.) I chose to make these pies smaller than the classicfeel free to increase the size to suit your needs. Using a small scoop (small Ice cream style scoop) drop batter onto greased cookie sheet about 2 inches apart. Bake for 6-8 minutes, until the tops no longer appear wet and just spring back when lightly touched. Transfer to a wire rack to cool.
6.) When completely cool, spread the bottom of one cookie with frosting and dip into graham cracker crumbs. Spread a very small amount of frosting on other half of cookie just to make them stick. Viola - S'mores Whoopie Pies!