Preheat oven to 350℉. Line muffin pans with cupcake liners.
In a stand mixer with a paddle attachment, or a bowl with a hand mixer, cream butter and sugar together. Add vanilla extract. Sift or whisk together flour, baking powder, and salt. Begin slowly adding dry ingredients and milk, alternating until each is well blended. Add chocolate chips and stir to combine with a spatula or large spoon.
In a separate bowl, add egg whites and whip until they form stiff peaks. Fold egg whites gently into the batter.
Fill each cupcake liner with approximately 3 tablespoons of batter. Bake for 15-18 minutes until cupcakes are cooked through the center. Test with a toothpick in the center of a cupcake to check for doneness, or lightly press the tops of the cupcakes to see if they spring back. Allow to fully cool before icing.
Chocolate Chip Cookie Dough Frosting
Spread the flour out on a baking sheet in a thin layer and bake in the oven at 350℉ for 5-10 minutes, until it reaches 160℉. This is for food safety and should not be skipped. Let the flour fully cool.
Cream together butter, shortening, and brown sugar until it's light and fluffy. Add vanilla extract and 2 tablespoons of milk. Slowly add confectioners' sugar and flour. If too thick, add an additional tablespoon of milk.
Mini chocolate chips can be mixed into the frosting, or they can be sprinkled on top. If you plan to pipe the frosting, I recommend sprinkling the chocolate chips on top of each cupcake because the tiny morsels easily clog icing tips.