In a large mixing bowl, beat together 1 cup of packed light brown sugar, ½ cup of room-temperature salted butter, 1 tablespoon of vanilla bean paste, 1 teaspoon of coffee extract, and ½ teaspoon of salt for about 4 minutes until fluffy and light in color. Add 1 large egg, mixing until fully incorporated.

In a separate bowl, sift together 1¾ cups of cake flour, ½ cup of Dutch process cocoa powder, ¼ cup of malted milk powder, 1 teaspoon of baking powder, ½ teaspoon of baking soda, and 1 teaspoon of espresso powder.

Gradually add the sifted dry ingredients to the wet mixture, alternating with ½ cup of buttermilk. Start with dry ingredients, mix until just combined, then add buttermilk and repeat.

Allow the batter to rest for 15 minutes. Preheat your oven to 350°F (175°C). Use a cookie scoop to portion the batter onto lined baking sheets, spacing them 2 inches apart. Bake for 9-12 minutes or until tops spring back.

After baking, remove cakes from the oven and let cool on baking sheets for 5-10 minutes. Transfer to a wire rack to cool completely.

In a mixing bowl, cream together ½ cup of cold unsalted butter and ½ cup of butter-flavored shortening. Add 1 tablespoon of vanilla bean paste and a pinch of salt, mixing until combined. Gradually incorporate 3 cups of powdered sugar, followed by 2 tablespoons of heavy cream, and 1 cup of marshmallow fluff.

Take half of the cooled chocolate cakes and scoop frosting onto each. Place remaining half on top, pressing slightly to create a sandwich.

Melt dipping wafers in a microwave-safe bowl, stirring until smooth. Dip whoopie pies halfway into melted chocolate, allowing excess to drip. Sprinkle with colored sprinkles if desired.