Ingredients:
Chocolate Cakes:
1 stick unsalted butter, softened
1 cup brown sugar, packed
1 large egg
1/4 cup + 2 tablespoons cocoa powder
2 cups all-purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
1 teaspoon salt
1 cup milk
1 teaspoon vanilla

Filling:
1 stick butter, soft
1/2 cup confectioners' sugar
pinch salt
3/4 cup  Marshmallow Fluff or marshmallow creme
1 teaspoon vanilla


Directions:

1. Preheat the oven to 350 degrees Fahrenheit. Lightly grease (or line with parchment) two baking sheets.
2. Prepare cakes:  In a large mixing bowl, using an electric hand mixer, cream together the soft butter,
   sugar and egg.
3. In a separate bowl, whisk together the cocoa, flour, baking powder, baking soda and salt.
4. Stir the vanilla into the milk.
5. Add the dry ingredients to the butter mixture alternately with the milk/vanilla mixture, beating till smooth.
6. Drop the dough by the 1/4-cupful, onto the prepared baking sheets, leaving about 2 inches between each cake.
7. Bake the cakes for about 15 minutes, or until they're firm to the touch. Remove them from the oven and
   cool completely on a rack.
8. Filling:  Beat together the butter, sugar, salt and marshmallow, then stir in the vanilla. Spread or pipe
   half of the cakes with the filling; top with the remaining cakes.