Blend oats in a high power blender for 30 seconds until a fine flour forms. Stir briefly to loosen (and to make sure they aren't tightly packed in base of blender - important!).
Add in banana and milk (and any other optional add-ins) and blend for 30 seconds on high, until mixture is smooth and lump-free.
Set mixture aside for 5 minutes to thicken slightly.
Switch waffle iron on and allow to reach cooking temperature.
Using kitchen towel, thoroughly coat all cooking surfaces of iron with coconut oil to avoid sticking.
Spoon batter evenly into waffle iron, being careful not to overfill. (Amount used depends on size of machine: I use ½ cup in my 8-inch iron, which gives me small/medium waffles that don't reach all the way to the edge, making them much easier to remove. I strongly recommend making smaller waffles with this recipe - see note below.)
Close lid and cook for 7-8 minutes (or until steam coming out reduces).
Open iron SLOWLY, and leave waffle in place for 30 seconds (this will help avoid sticking) before gently removing with a flat knife. (If waffle is still sticking to iron, see my tips above!)
Repeat process for remaining batter - greasing iron between each waffle with coconut oil - and store waffles on a plate in warm oven until ready to eat.
Serve with maple syrup, coconut cream, bananas, berries, nuts and/or cinnamon. Enjoy!