1-Preheat your oven to 350 degrees Fahrenheit and prepare your cupcake tins with liners.

2-In a medium bowl, lightly mix 4.75 ounces of egg whites, 1/4 cup of milk, and vanilla extract. Set this mixture aside for later use.

3-In a large mixing bowl, combine all dry ingredients: sifted cake flour, granulated sugar, baking powder, and salt. Mix on low speed until just combined.

4-Add the softened unsalted butter and the remaining milk to the dry ingredients. Mix on low speed until the dry ingredients are incorporated, then increase the speed to medium and mix for 1.5 minutes.

5-Scrape down the sides of the bowl to ensure all ingredients are well incorporated.

6-Gradually add the egg mixture in three batches, beating for 20 seconds between each addition and scraping the sides of the bowl each time.

7-Fill your cupcake liners about two-thirds full to allow room for rising.

8-Bake for 12 to 15 minutes, or until a toothpick inserted in the center comes out clean.

9-Allow the cupcakes to cool in the pan for 5-10 minutes, then transfer them to a wire rack to cool completely (about an hour) before frosting.

10-Cream 2 cups of unsalted butter on low speed for 2 minutes until smooth.

11-Gradually add 6 cups of sifted powdered sugar on low speed until incorporated.

12-Increase the speed to medium, add the vanilla extract and salt, and mix for 3 minutes.

13-Add milk one tablespoon at a time until you reach your desired consistency.

14-If the frosting is too thin, add more powdered sugar (up to 3 additional cups).