Preheat a waffle iron according to instructions.
Whisk egg yolks in a large bowl until light and fluffy. Add flour, milk, and melted butter and mix to combine. Whisk in sugar, then mix in baking powder, salt, and vanilla just until smooth. Being careful not to overmix, fold in egg whites and cooked sausage.
Spray the preheated waffle iron with a nonstick spray. Pour batter onto the hot waffle iron and cook until golden brown and the light turns green or stops steaming (about 3-5 minutes.)
Serve with maple syrup and a side of eggs, if desired.