Wickedly Good Whoopie Pies: Soft and Rich

Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper or silicone mats.

In a medium bowl, sift together the flour, cocoa powder, baking powder, baking soda, and salt.

In a stand mixer, beat 170g of butter and granulated sugar on high for 3 minutes until pale and voluminous.

Add the egg and 1 tablespoon of vanilla extract, beating until the mixture reaches a whipped cream consistency.

Set mixer to low. Add the dry ingredient mixture in three parts, alternating with the buttermilk, mixing only until streaks disappear.

Using a 2-tablespoon cookie scoop, drop batter onto prepared sheets. Bake for 10 minutes until domes are springy. Transfer to a wire rack to cool completely.

Prepare the filling by beating the remaining 225g of butter, marshmallow fluff, powdered sugar, and 1 teaspoon of vanilla until aerated and fluffy.

Spread or pipe a generous amount of filling onto the flat side of one cooled cake and top with another to create a sandwich.