In a mixing bowl, whisk together the flour, baking powder, and salt. Set aside.
2 1/2 cups all purpose flour, 1/2 tablespoon baking powder, 1/2 teaspoon table salt
Using a stand mixer or a hand mixer, beat together the room-temperature butter and granulated sugar. Beat until light and fluffy, about 3 to 6 minutes.
12 tablespoons unsalted butter, 3/4 cup granulated sugar
Beat in the milk, then the egg, and then the vanilla.
1/4 cup milk, 1 egg, 1 teaspoon vanilla extract
Add the flour mixture and beat until just combined. The dough batter will be very sticky.