Preheat the oven to 350°F. Place a cupcake liner into each of the cups of a 12-cup cupcake pan. Set aside.

Cake Time: In a medium bowl, whisk together the dry ingredients: flour, baking powder, baking soda and salt. Add butter and sugar into the bowl of a stand mixer fitted with the paddle attachment. Start on low speed, then increase to high speed, beating the butter and sugar together until fluffy. Scrape down the sides of the bowl as needed. On medium speed, mix in the whole egg and vanilla until well incorporated and fluffy. Scrape the bowl down as necessary.

Set the mixer on low speed and slowly begin adding the dry ingredients in fourths, alternating each increment with a bit of buttermilk, until both are completely incorporated. Scrape down the bowl and the paddle attachment as necessary. Be careful not to overmix this batter—it will make the cupcakes tough.

In a small bowl, energetically whisk the egg white until it’s foamy and fluffy. This will take several minutes. Carefully fold the egg white into the cupcake batter. Fold sprinkles into batter.

Spoon batter evenly into each cupcake liner. Bake for 15-20 minutes.

Allow cupcakes to cool on a cooling rack for 2 hours or until completely cool.

Frosting Time: In the large bowl of a stand mixer set on medium speed with the whisk attachment, beat the butter for a few minutes until smooth. Set the mixer to low speed and slowly add in the confectioners’ sugar, buttermilk, and vanilla. Once all of the ingredients are lightly incorporated, increase the stand mixer to high speed. Scrape down the sides of the bowl as needed. Beat until fluffy—about 5 minutes. If your frosting is too runny, add in more sugar; if it’s too thick, add in small amounts of buttermilk.

Cupcake Time: Once the cupcakes are completely cooled, it’s time to frost! Add frosting into a piping bag and squeeze or twist the end slightly to compact the frosting towards the tip of the bag. Attach your piping tip of choice. Starting from the center of the cupcake, squeeze the bag with even pressure as you pipe outward, in a circle. Swirl the frosting in a circle until you reach the center/top of the cupcake. Apply gentle pressure downward, stop squeezing the piping bag and pull it up to finish. It takes a couple tries, but you’ll get the hang of it!

Optional: top with sprinkles. Enjoy!