In a large mixing bowl, whisk together the flour, sugar, and baking powder.  With an electric mixer, beat the egg whites until stiff peaks form.  Set aside.  In another mixing bowl, whisk the egg yolks, whole milk, and vanilla.  Slowly drizzle in the melted butter, while whisking.  Pour the wet ingredients into the dry ingredients and stir until just combined.  Gently fold in the egg whites.

Cook in a waffle iron that has been sprayed with cooking spray, according to manufacturer’s directions.  In the Cuisinart Griddler, with the waffle plates clipped in, preheat to 400 degrees and cook the waffles for 5-6 minutes, until light golden brown.