2 cups all purpose flour
1 teaspoon salt
1/2 teaspoon baking soda
2 large eggs, separated
4 tablespoons unsalted butter, melted
1 3/4 cups buttermilk*
pinch of cream of tartar
After heating the waffle iron whisk together flour, salt and baking soda in a large bowl. In a separate bowl whisk together the egg yolks, butter and then the buttermilk. Beat the egg whites and cream of tartar with an electric mixer on medium high speed til stiff peaks form, about 2 minutes. Make a well in the center of the dry ingredients, pour the buttermilk mixture into the dry ingredients and whisk very gently just til incorporated. A few lumps should remain. Fold the whipped egg whites into the batter.
*If you don't have buttermilk you can add 2 tablespoons of white vinegar or lemon juice to the 1 3/4 c milk and let it sit for about 5 minutes.
The batter should be lumpy. If you overmix the batter you will have heavy dense waffles.
