Mix the dry ingredients: Add the flour, sugar, baking powder and salt to a bowl. Stir very well until mixed.
Mix the wet ingredients: In a large measuring jug, whisk together the egg YOLKS, buttermilk, oil and vanilla extract until smooth.
Beat the gg whites: Beat the egg WHITES in a clean bowl with electric beaters until stiff peaks form.
Make the batter: Pour the wet ingredients into the bowl with the dry ingredients and stir just to combine. Add the beaten egg whites and carefully fold in just until incorporated. Fold in the chocolate chips with just a couple of light stirs. Do NOT overmix, or the waffles will be dense.
Bake waffles: Preheat your waffle iron on medium-high. Lightly grease and bake waffles according to your manufacturer's instructions. I use about 1/4 cup of batter per waffle, and I scoop it with a cookie scoop to make less of a mess.
Serve the waffles hot right out of the waffle iron - that's when they're the crispiest!
To freeze: Place the waffles in a single layer on a lined baking sheet. Freeze for about an hour or until firm. Pack into freezer bags and label with the name and the date.