Mix the flours, sugar, baking powder, salt and baking soda together. Put in a mixing bowl and turn on speed one, using the paddle attachment. Quickly add the buttermilk. Scrape down the sides and bottom of the bowl and the paddle with a rubber spatula. Slowly pour the melted butter into the bowl while the mixer is running. Slowly pour the egg yolks into the bowl while the mixer is running. Transfer this batter to another bowl. Whip the egg whites to medium peaks in a new bowl with the whisk attachment of your mixer. Fold in one-third of the whites with a rubber spatula. Now fold in the remaining whites.
To cook the waffles, turn a waffle iron on to medium heat. Spray the waffle iron with cooking spray. Scoop batter onto the iron, enough to fill. Close and cook for 2 1/2 minutes. Let cool on a wire rack. Repeat.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Sarah Sanneh, Pies 'n' Thighs, Brooklyn, NY