For the cookies:
- 1 1/2 cups all-purpose flour
- 1/2 teaspoon baking powder
- 1/2 teaspoon fine salt
- 1/4 teaspoon baking soda
- 5 tablespoons unsalted butter, softened
- 2/3 cup granulated sugar
- 1 teaspoon vanilla extract
- 1 large egg
- 1/3 cup milk
- 3/4 cup blueberries
- Cooking spray
For the filling:
- 4 ounces cream cheese, at room temperature
- 3 tablespoons unsalted butter, softened
- 1 teaspoon finely grated lemon zest
- 1 tablespoon fresh lemon juice
- 1/2 teaspoon vanilla extract
- Pinch of salt
- 1 1/2 cups confectioners' sugar
Position racks in the center and lower third of the oven and preheat to 375 degrees F. Make the cookies: Whisk the flour, baking powder, salt and baking soda in a medium bowl. Beat the butter, sugar and vanilla on medium-high speed in a stand mixer fitted with the paddle attachment until light and fluffy, about 5 minutes. Beat in the egg until combined, scraping down the bowl. Reduce the mixer speed to low and beat in the flour mixture and milk in 3 alternating batches. Fold in the blueberries with a rubber spatula.
Line 2 baking sheets with parchment paper; coat with cooking spray. Arrange mounds of batter, about 2 tablespoons each, 2 inches apart; smooth the tops with a damp finger. Chill until firm, 30 minutes.
Bake the cookies until lightly golden, rotating the pans halfway through, 10 to 12 minutes. Let cool on the pans for 5 minutes, then transfer to a rack to cool completely.
Assemble the whoopie pies: Spread 2 tablespoons of filling on the flat side of 6 cookies and sandwich with the remaining cookies. Serve immediately or refrigerate, covered, overnight.
Photograph by Con Poulos