In medium bowl, mix all dry ingredients and set aside.
In a small bowl, mash banana with a fork. Add all other wet ingredients and mix well by hand. (If it's a little bit lumpy that's ok.)
Pour the wet ingredients into dry and mix well.
Ladle the batter into the waffle iron and cook until crispy. Watch closely because they cook very quickly!
Serve immediately with syrup or sliced banana.
Notes
If you don't want to buy oat flour it's extremely simple to make. Just take regular oatmeal, and grind it in either a NutriBullet or food processor into a powder form. This is the most economical way to use oat flour. You can substitute butter for the coconut oil, if preferred.