Preheat oven to 375 degrees and line a baking sheet with parchment paper. Set aside.

In a large bowl, beat butter until light and fluffy, about 1 minute. Add in both sugars, and cream until well combined. Add in eggs, one at a time, beating well after each addition. Set aside.

In a separate bowl, sift together flour, cocoa powder, baking soda, salt, and espresso powder.

Alternately add the dry ingredients and the buttermilk and water to the butter mixture, beginning and ending with the dry ingredients. Stir in vanilla extract.

(The batter will be a consistency in between cookie dough and cake batter).

Drop dough by large Tablespoons onto the prepared cookie sheet, spacing each about 2" apart.

Bake for 6-7 minutes, or until the cookies are set (puffy but soft to the touch). Allow to cool completely before frosting.

In a bowl, beat butter and marshmallow creme until well combined. Add in heavy cream, vanilla extract, and 1 1/2 cups powdered sugar. If the filling is too thin, add in the remaining 1/2 cup of powdered sugar. Add in a pinch of salt to cut the sweetness, if desired.

With a piping bag, add frosting to the flat side of half of the cookies. Top with remaining half of cookies and slightly press down.

Roll the edges of cookies in crushed graham crackers.

Enjoy!