Whoopie Pies

Instructions

1. 1

   Preheat oven to 375°F (190°C). Line two large baking sheets with parchment paper. This prevents the cakes from sticking and ensures even baking.

2. 2

   In a medium bowl, whisk together the dry ingredients for the cakes: all-purpose flour, cocoa powder, baking soda, and salt. Set aside.

3. 3

   In a separate large bowl, whisk the packed light brown sugar, buttermilk, vegetable oil, egg, and 1 teaspoon of vanilla extract until smooth and well combined.

4. 4

   Gradually add the dry ingredient mixture to the wet ingredients. Mix on low speed with an electric mixer or by hand with a spatula until just combined. Do not overmix; a few small lumps are okay.

5. 5

   Using a 2-tablespoon cookie scoop or two spoons, drop mounds of batter onto the prepared baking sheets, about 2 inches apart. This should yield about 24 cake halves.

6. 6

   Bake for 10-12 minutes, or until the tops are set and spring back when lightly touched. Let the cakes cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely. This step is crucial for a non-melty filling.

7. 7

   While the cakes cool, prepare the filling. In a large bowl using an electric mixer, beat the vegetable shortening and softened unsalted butter on medium-high speed until light and fluffy, about 3 minutes.

8. 8

   Add the sifted powdered sugar, marshmallow fluff, and the remaining 1 teaspoon of vanilla extract to the butter mixture. Beat on low speed until combined, then increase to medium-high and beat for another 2-3 minutes until the filling is very smooth and airy. If it's too stiff, beat in the heavy cream, one teaspoon at a time, until you reach a thick, spreadable consistency.

9. 9

   Once the cakes are completely cool, pair them up by size. Pipe or spread a generous amount of filling onto the flat side of one cake half. Gently press another cake half on top, flat side down, to create a sandwich. Repeat with the remaining cakes and filling.

10. 10

    For the best texture and flavor, individually wrap the assembled whoopie pies in plastic wrap and chill in the refrigerator for at least 30 minutes before serving. This allows the cakes to soften and the flavors to meld.