5 or 55, who doesn't love a whoopie pie? Maybe it's the shape, or maybe it's the gooey filling, but there's something about them that makes them so fun to eat. I wanted to delight my colleagues with something deliciously festive for Halloween, so I turned to Bon Appetit and knew these whoopie pies, with their grown-up flavors, were it. They agreed and I have a good feeling you will, too. —misslofox
To make the filling, beat sugar and butter in large bowl in an electric mixer until fluffy, about 2 minutes. Add marshmallow creme and maple extract; beat until blended and smooth. Set aside.
Sift first 7 ingredients into large bowl. Using electric mixer, beat butter and both sugars in another large bowl until blended. Gradually beat in oil. Add eggs 1 at a time, beating to blend between additions. Beat in pumpkin. Add dry ingredients in 2 additions alternately with milk in 1 addition, beating to blend between additions and occasionally scraping down sides of bowl. Cover and chill batter 1 hour.
Arrange 1 rack in bottom third of oven and 1 rack in top third of oven; preheat to 350°F. Line 2 baking sheets with parchment; spray lightly with nonstick spray. Spoon batter onto baking sheet to form cakes (about 3 level tablespoons each; about 12 per baking sheet), spacing apart. Let stand 10 minutes.
Bake cakes until tester inserted into centers comes out clean, about 20 minutes, rotating sheets halfway through baking. Cool cakes completely on baking sheets on rack. Using metal spatula, remove cakes from parchment.
Line cooled baking sheets with clean parchment; spray with nonstick spray, and repeat baking with remaining batter.
Spoon about 2 tablespoons filling on flat side of 1 cake. Top with another cake, flat side down. Repeat with remaining cakes and filling.