Add egg white to a bowl with a pinch of salt. Beat with a hand-held mixer until stiff peaks form. Set aside.
In a separate bowl, add egg yolk, Greek yogurt, milk, maple syrup, avocado oil, vanilla extract, baking powder, and baking soda. Whisk until well combined.
Add beaten egg whites and flour, gradually. Stir gently until all the flour is incorporated. Let the batter rest for 5 minutes.
Meanwhile, heat your waffle iron and spray it with some cooking spray.
Drop 1/4 cup of the batter onto the waffle iron. Cook waffles for 3-4 minutes or until you see the steam has stopped coming out. Repeat with the remaining batter. Place the waffles onto the wire rack so they do not become soggy.
Serve with fruit, maple syrup or chocolate sauce.
Notes
Store: Refrigerate in air circulating container for up to a week. To heat up, place in a toaster for a few minutes.Freeze: In a reusable plastic bag for up to 3 months. To thaw, place in a toaster for a few minutes.You do not have to separate eggs if you do not want to, but beating egg whites separately will give lighter waffles.