Preheat waffle iron.
Add egg whites to the bowl of stand mixer and beat until soft peaks form. Set aside.
In a separate large bowl combine egg yolks, apple cider vinegar, coconut milk, vanilla, and maple syrup.
Sift in the cassava flour 1/2 cup at a time and mix until fully combined.
Mix in the salt, baking soda, and cinnamon.
Allow batter to stand for 5 minutes.
Gently fold in the egg whites with a rubber scraper. Don't over-mix here otherwise you'll knock the air out of the batter.
Spoon batter into hot waffle iron. Cook until golden brown and crispy.
Serve with your favorite fruit compote or some amazing vanilla bean ghee like this one from Fourth & Heart!