1. Preheat over to 350
2. Combine all dry ingredients (minus sugar) into a small bowl and set aside. Combine the milk and vanilla in a small bowl and set aside.
3.. Cream the butter in a large mixing bowl or the bowl of a stand mixer with a paddle attachment. Slowly add in the sugar until fully combined and fluffy.
4. Add in the egg whites one at a time, making sure to combine each before adding the other.
5. dd in about ½ of the dry mixture while mixing on a low speed. Alternate adding in dry and wet ingredients until they are all combined. Mix for an additional 3 minutes on a medium speed.
6. Prepare the 2 8 or 6″ cake pans with nonstick baking spray and distribute the batter evenly between them.
7. Bake for about 30-35 minutes or until a toothpick inserted comes out clean.
8. Let cool completely before frosting.