1Preheat oven to 180°C (approximately 350°F.
2In a mixing bowl, whisk flour, cocoa, baking powder and baking soda and set aside.
3In another bowl, beat butter and sugar until mixture is creamy.
4Add eggs one at a time, stirring each one well before adding the next.
5Add vanilla extract and food dye.
6Beat until mixture is smooth.
7Alternately stir in buttermilk and flour mixture, stirring well after each addition, so that flour mixture is added last.
8On parchment paper, draw circles in the desired size for whoopee pies.
9Leave space about 3 cm (approximately 11/4 inches) between each circle.
10Using a pastry bag, pipe dough onto each circle.
11Bake in preheated oven for about 10 minutes.
12Remove and let cool on a rack.
13For the filling, mix butter until it is cream and stir constantly, while gradually adding powdered sugar.
14Beat for a few minutes until mixture is fluffy.
15Add cream cheese and mix slowly at the lowest speed until well-blended.
16Add marshmallow cream and mix until smooth and creamy.
17Place filling in a pastry bag. Pipe filling onto cookie and top with a second cookie.
18Refrigerate until ready to serve