Vanilla Cupcakes

1. Preheat oven to 350º F.
2. Whisk together the flour, baking powder, and salt in a medium bowl and set aside.
3. In a stand mixer fitted with a paddle attachment, cream the butter and sugar together on medium speed until well combined.
4. Add the egg whites and vanilla with the mixer on medium speed and scrape down the sides of the bowl as needed.
5. Add the sour cream and mix until combined.
6. With the mixer on low, add in the flour mixture and milk. Scrape down the sides of the bowl as needed and mix just until it is incorporated.
7. Line a cupcake pan with 12 cupcake liners and carefully divide the batter evenly among them, filling each only about two thirds of the way.
8. Bake for 22-24 minutes until a toothpick inserted into the center of the cupcakes comes out clean.
9. Cool for 5-10 minutes in the pan before gently pulling the cupcakes out of the pan to cool completely on a cooling rack.

Black Cocoa Frosting

1. Cream the butter until smooth.
2. Sift in the powdered sugar and black cocoa. Add the vanilla and cream.
3. Mix on low just until combined. Cover the bowl with plastic wrap and chill until ready to use.

Assembly

1. Once the cupcakes have cooled, scoop the frosting into a pastry bag fitted with a Wilton 1M or similar piping tip.
2. Starting at the outside rim of the cupcake, begin to pipe the frosting in a clockwise motion, moving to the center until you have covered the entire top in a beautiful swirl design. Repeat this with the remaining cupcakes.
3. Top each cupcake with sprinkles. Enjoy!