Preheat the waffle iron right away, so it will be ready when your batter is.
In a small bowl, combine the coconut flour, tapioca, egg, coconut oil, maple syrup, and baking powder. Use a whisk to break up any clumps and make it as smooth as possible. If your egg or maple syrup are cold from the fridge, the batter will be very thick, but it will still cook just fine. For a runnier batter, use eggs and maple syrup that are at room temperature.
Spray both sides of the waffle iron with spray oil, then pour the batter into the center of the waffle iron. (It doesn't have to fill the waffle iron all the way, as long as it's in the center.) Close the waffle iron and let the waffles cook until the "ready" light goes off, about 3 to 5 minutes.
You'll know the waffles are done when you open the waffle is golden on the outside. If you find that the sides of the waffle are sticking when you open it, or if they are splitting apart, you'll know you need to cook it a little longer.
Serve the waffle right away with your favorite toppings. These won't be as crispy as a waffle made with white flour, but they are very sturdy and have a great flavor on their own-- you might not even need any extra maple syrup! Leftover waffles can be stored in the fridge and reheated in the toaster, if you need to.
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Notes
If you don't want to use tapioca or arrowroot starch, you can substitute 1 teaspoon of coconut flour for that, with somewhat similar results. They won't be quite as crispy or sturdy that way. If you need a sugar-free pancake, you might be able to swap the maple syrup for a sugar-free option, instead, but I haven't tried omitting it entirely. Water might work as a liquid swap, too, but I can't guarantee that since I haven't tested it yet.