Whisk the egg, almond flour, and baking powder in a small bowl until the mixture looks smooth, then stir in the mozzarella and let the batter sit briefly. The batter should look thick and spoonable, with the cheese evenly coated instead of clumped at the bottom.

Heat the waffle iron according to its regular waffle setting before adding any batter. A fully heated iron helps the outside set quickly, which gives you better browning and less sticking.

Coat both sides of the hot waffle iron with cooking spray or coconut oil, add half the batter, and gently spread it from the center with a spoon before closing the lid. Keep the layer even and do not overfill, or the batter can spill and cook unevenly.

Cook the chaffle for about 3 minutes, then check that it releases easily before removing it and repeating with the remaining batter. When the steam slows down, the chaffle is usually close to done, and it may still feel soft straight off the iron.

Rest the cooked chaffles for 2 to 3 minutes before serving. That short rest is when they firm up and become noticeably crisper.