Separate Eggs. If egg whites are not already room temp, allow egg whites to stand at room temp. for 30 mins.
Grease 3 Eight-inch round cake pans with shortening, then coat with flour and set aside. In a medium bowl mix flour, baking powder, baking soda and salt; set aside.
Preheat oven to 350 Deg. In a large mixing bowl beat butter with an electric mixer on high for 30 seconds. Add sugar and vanilla; beat until well combined.
Add egg whites and beat on medium-high for 3 mins. Alternate adding flour mixture and buttermilk mixture about a ⅓ of each at a time. Beat on low after each addition until well combined.
Divide batter amongst 3 prepared pans.
Bake in preheated oven 30-35 mins, or until toothpick comes out clean.
When done immediately stick into freezer to lock in moisture, if unable cool on wire racks for at least 10 mins before removing cakes from pans. Cool thoroughly before frosting.