Preheat oven to 350*F. Grease, line with parchment and flour 2-8" round cake pans.In a medium bowl, combine the egg whites, whole egg, 1/4 cup of the milk, and vanilla. Set aside.In the bowl of an electric mixer, fitted with a paddle attachment, combine the dry ingredients together on low speed for approximately 30 seconds. Add butter, one piece at a time, about every ten seconds until it is a fine crumbly mixture. Add the remaining 3/4 cup milk and mix on medium speed for about 1 1/2 minutes.Scrape the sides of the bowl. Add egg mixture in three additions, beating on medium speed for 20 seconds between each addition. Mix on medium speed for about 4 minutes until light and fluffy. Scrape the bowl. Divide into pans, smooth, bake 35-45 mintues. Do not check before 20 minutes. A toothpick should come out with a few crumbs attached. Cool 10 minutes then remove from the pans to a wire rack.