Preheat oven to 335˚F. Using an electric mixer combine dry ingredients for cake. In another bowl combine egg whites, 3/4 cup buttermilk, 1/4 cup oil, and vanilla.
Using mixer add butter to flour mixture until crumbly mixture forms. Combine remaining buttermilk with oil. Add oil mixture to flour mixture and mix for 2 full minutes.
Add egg white mixture to batter in 3 lots, mixing well between each addition.
Pour batter into 2 greased and lined 8” cake pans. Bake for 35-40 minutes or until knife inserted in center comes out clean. Tap cake pans onto cutting board as soon as they are out of the oven to help even out the cakes. Allow to cool for 10 minutes before running knife along edges and removing from pans. Allow to cool for at least 30 minutes in refrigerator before frosting.