Preheat your waffle iron and melt butter over low, if using stovetop.
In a large bowl, combine all dry ingredients: flour, baking powder, and sugar. Whisk together.
Divide the egg yolk and whites into two separate medium sized bowls.
Add the milk, butter, and vanilla extract to the yolk bowl and mix to combine.
With a hand or stand mixer, beat the egg whites on medium-high until stiff peaks form. Should only take a couple minutes and makes the waffles so fluffy!
Pour yolk and milk mixture into the dry ingredients and stir or whisk until combined, being careful not to over-mix. Add the egg whites and fold them into the batter gently.
Heat oven to 250-275 degrees to keep cooked waffles warm and crisp. Lightly grease waffle iron (I like to brush on a little butter). Use a measuring cup to pour batter onto waffle iron, until wells are almost covered. Close the iron and cook for about 4 minutes or until golden brown. (Tip: This is a great time to prep toppings or tidy up the kitchen. If you're like me though, be sure to set a timer!)
Place cooked waffles in a single layer, directly on rack in oven. When ready, top and serve!