Makes about 12 cupcakes 1 1/2 cups flour 1/4 teaspoon salt 1 1/4 teaspoons baking powder 1/2 cup butter, room temperature 1 cup sugar 1 egg plus 2 egg whites 1/2 cup whole milk 1 1/2 teaspoons vanilla bean paste
Preheat oven to 350 degrees F. Line a muffin tin with cupcake liners. Sift flour, salt, and baking powder into a bowl and set aside. Beat butter and sugar in a stand mixer on medium speed until very light and fluffy, about 3 to 4 minutes.
Add in the egg and beat to combine. Add in the egg whites, one at a time, and beat to combine.
Combine milk and vanilla bean paste together in a cup. Add the flour mixture and milk mixture to the batter in alternating additions, starting and ending with the flour. Once the last bit of flour has been added. beat just to combine - do not overbeat.
Divide batter among the muffin tins. Bake in the oven for about 15 to 20 minutes, until the tops are lightly golden and a toothpick inserted in the center comes out clean. Let cool on wire rack.