Preheat the waffle maker and set aside.
In a large mixing bowl, whisk the flour, sugar, baking powder, and salt together until well combined. Set aside.
In a separate large mixing bowl, whisk together the milk, oil, vanilla extract, and egg yolks until fully combined. Add the dry ingredients to the wet ingredients and mix together until just combined.
Add the egg whites to a clean mixing bowl and beat to stiff peaks.
Gently fold the egg whites into the batter until just combined.
Spray the waffle maker well with nonstick cooking spray. Scoop or pour some of the batter onto the hot waffle iron (the amount will depend on your waffle maker), close the lid, and cook according to your waffle maker’s instructions or until crisp and golden brown. Repeat with the remaining batter.
Serve warm with pure maple syrup, fresh fruit, or toppings of choice.