Crack the egg into a small bowl and whisk with a fork. Add the mozzarella and stir to combine.
Spray the waffle iron with non-stick spray.
Pour half of the egg mixture into the heated waffle iron and cook for 2-3 minutes.
Remove waffle carefully and cook remaining batter.
Serve warm with butter and sugar-free syrup.
Notes
This is the BASIC chaffle recipe and nothing more is needed, however adding 1 teaspoon of coconut flour or almond flour + 1/4 teaspoon of baking powder will give these a better texture. For a breakfast chaffle, try adding a splash of vanilla or a dash of cinnamon. You may also add sweetener directly to the batter if you'd like. We highly recommend mozzarella cheese for a basic chaffle as it has the most neutral flavor (it won't taste cheesy!). If you're making a savory chaffle and want that cheesy flavor, you can use cheddar or any other type of shredded cheese you like.