Instructions
Preheat oven to 325. Line muffin pan with cupcake liners, set aside.
In a large bowl, using a mixer, cream together butter and sugar for 5 minutes until light and fluffy and multiplied several times in volume.
Add in egg yolks and vanilla, mixing until fully incorporated and set aside.
In another bowl, combine flour, baking powder and salt.
Gradually add dry ingredients into wet ingredients, alternating with the buttermilk.
Mix until batter is fluffy but be careful not to over-mix.
In another bowl, using mixer, beat egg whites until stiff peaks and thick.
Very gently fold egg whites into batter and mix until just incorporated, do not overmix.
Pour batter into cupcake liners. (I used an ice cream scooper per each cupcake.)
Bake for 12-15 minutes.
Remove from oven and let cupcakes cool.