Whoopie Pies

Whoopie Pies

Cakes:
2 cups flour
½ cup cocoa powder
1 teaspoon baking soda
½ teaspoon salt
1 cup packed brown sugar
8 Tablespoons (1 stick) unsalted butter, softened but still cool
1 large egg, room temperature
1 teaspoon vanilla
1 cup buttermilk

Filling:
12 Tablespoons (1 ½ sticks) unsalted butter, softened but still cool
1 ¼ cups confectioners’ sugar
1 ½ teaspoons vanilla
1/8 teaspoon salt
2 ½ cups Marshmallow Fluff

For the cakes adjust oven racks to upper-middle and lower-middle positions and heat oven to 350 convection oven. Line 3 baking sheets with parchment paper. Whisk flour, cocoa powder, baking soda, and salt in a medium bowl.

With electric mixer on medium speed, beat sugar and butter in large bowl until fluffy, about 4 minutes. Beat in egg until incorporated, scraping down sides of bowl as necessary, then beat in vanilla. Reduce speed to low and beat in 1/3 of flour mixture, then half of buttermilk. Repeat with half of remaining flour mixture, then remaining buttermilk, and finally remaining flour mixture. Using rubber spatula give patter final stir.

With a large Ziploc bag fill with batter. Cut tip and pipe onto cookie shapes circulating as you go to make a circle. Bake until cakes spring back when pressed, 15-18 minutes. Cool completely on baking sheets for at least 1 hour.

For the filling with an electric mixer on medium speed, beat butter and sugar together until fluffy, about 2 minutes. Beat in vanilla and salt. Beat in Fluff until incorporated, about 2 minutes. Refrigerate filling until slightly firm, about 30 minutes. Bowl can be wrapped and refrigerated up to 2 days.

Dollop 1/3 cup filling on center of flat sides of cakes. Top with flat side of remaining cakes and gently press until filling spreads within an edge of the cake. Serve. Whoopie pies can be refrigerated in airtight container for up to 3 days.