Combine the flour, salt, sugar, baking soda.Mix together the buttermilk and the egg yolks. Stir in vanilla. Spray the waffle iron well and preheat it. Stir the wet into the dry ingredients.Beat the egg whites in a separate bowl with a whisk or electric mixer (make sure bowl and mixer are spotlessly clean) until they hold soft peaks. Stir them gently into the batter.Spread a ladleful or so of batter onto the waffle iron and bake until the waffle is done, usually 3 to 5 minutes, depending on your iron. Spray iron with cooking spray between waffles as needed.To make Maple Cream Cheese spread, sim