Whoopie Pies
Cakes Serves 6
2 c all-purpose flour
1/2 c Dutch-processed cocoa
1 tsp baking soda
1/2 tsp table salt
1 c packed light brown sugar
8 tblsp unsalted butter (1 stick), softened but still cool
1 egg, room temperature
1 tsp vanilla extract
1 c buttermilk
Filling
6 tblsp unsalted butter,
softened but still cool
5/8 c confectioners’ sugar
3/4 tsp vanilla extract
pinch table salt
1 1/4 c Marshmallow Fluff
For the cakes: Line 2 baking sheets with parchment paper. Whisk flour, cocoa powder, baking soda, and salt in medium bowl. With electric mixer on medium, beat sugar and butter in large bowl until fluffy, about 4 min. Beat in egg, and vanilla. Reduce speed to low and beat in one-third 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 batter final stir. Using 1/3 c measure, scoop 6 mounds of batter onto each baking sheet, spacing mounds about 3 in. apart. Bake until cakes spring back when pressed, 15-18 min, switching and rotating pans halfway through baking at 350. Cool completely on baking sheets, at least 1 hour.
For the filling: With electric mixer on medium speed, beat butter and sugar together until fluffy, about 2 min. Beat in vanilla and salt. Beat in Fluff until incorporated, about 2 min. Refrigerate filling until slightly firm, about 30 minutes. (Bowl can be wrapped and refrigerated for up to 2 days.) Dollop 1/3 c filling on center of flat side of 6 cakes. Top with flat side of remaining 6 cakes and gently press until filling spreads to edge of cake. Serve. (Whoopie pies can be refrigerated in airtight container up to 3 days.)