Preheat a waffle maker and brush it liberally with melted butter. Whisk together the almond flour, tapioca flour, baking powder, and salt in a mixing bowl, preferably with a spout. Add the eggs, applesauce, and vanilla and mix to combine.
Following the directions for your waffle maker regarding batter quantity and cook time, pour in the batter and cook the waffle until done. Remove and transfer to a low oven to keep warm. Regrets the waffle iron and repeat with the remaining batter.
Serve the waffles hot with butter and maple syrup. Store leftovers in the fridge for up to 1 week or in the freezer for up to 6 months.