1/2 cup (113g) butter, softened
1 cup (200g) granulated sugar
1/2 cup (123g) whole milk, at room temperature
1 teaspoon vanilla extract
1/4 teaspoon pure almond extract, optional
1 1/2 cups (180g) of pastry flour
2 teaspoons of baking powder
4 (120g or 4 ounces) egg whites, at room temperature
Preheat the oven to 350°F. Prepare an 8×8 square baking pan with butter and flour or baking spray.
Beat the butter at medium speed with a hand blender until it is creamy, about 3-4 minutes.
Gradually add sugar, beating until light and fluffy.
Stir in the milk and vanilla. (If you are adding almond extract, add it here)
Sieve the flour and baking powder together; add to the butter mixture alternately with the milk mixture, starting and ending with the flour mixture. Beat at a low speed until it is mixed after each addition.
Beat egg whites at medium speed until stiff peaks form; fold gently into dough. Pour dough into prepared pans.
Bake at 350° for 35-38 minutes or until a wooden spout inserted in the center comes out clean.
Cool in the pan on a wire rack for 10 minutes.
Optional: Cover with white glaze.