Grease & flour pans (1 - 9 by 13 or 2 - 9 inch round).
Mix flour, baking powder, baking soda, and salt in medium bowl and set aside.
Beat shortening with an electric mixer for about 30 seconds on medium speed in large bowl.
Add sugar and vanilla. Beat until combined.
Add egg whites and beat for about 30 seconds.
Add flour mixture and buttermilk. Beat until combined.
Beat on high for an additional 30 seconds.
Spread batter into the pan (s)
Bake in 350 degree oven for 20 to 25 minutes (30-35 for 9 by 13 pan).