Preheat a mini waffle maker and lightly coat both plates with avocado oil spray.
In a small bowl, whisk the eggs, mayonnaise and water until completely smooth.
Add the almond flour, baking powder and salt. Whisk until no lumps remain and the batter is thin and pourable.
Pour one quarter of the batter, about 2 tablespoons, into the waffle maker and close the lid. Cook for 2 1/2-3 minutes, until the steam slows down and the chaffle is golden.
Lift the chaffle out with a fork and repeat with the remaining batter to make 4 chaffles in total.
Cool the chaffles on a wire rack for 2-3 minutes. They firm up as they cool and become soft, bready slices that are perfect for sandwiches.