To prepare Oat Pancakes: In a large bowl combine the oats, flours, baking powder, and salt. Make a well in the center of mixture; set aside. In a medium bowl combine the egg whites, buttermilk, oil, honey (if desired), and vanilla. Add egg white mixture all at once to flour mixture. Stir just until moistened (batter should be lumpy). Cover batter; allow to stand at room temperature for 15 to 30 minutes.