1) In a large bowl, whisk together dry ingredients. In a small bowl, lightly whisk the egg yokes then whisk in the milk and melted butter. Add the yoke mixture to the flour mixture. Stir until well blended. The batter will be lumpy.
2) In a clean bowl, using an electric mixer on high speed, beat the egg whites until stiff, but not dry, peaks form. Using a silicon spatula, fold about 1/3 of the egg whites to lighten it. Then fold in the rest just until no white streaks remain. Use the batter right away.