To begin, bring frozen blueberries to a low boil in a small covered saucepan.
Then, add in maple syrup, water, and flour, and turn the heat down to low-medium. Cook for another 10 minutes.
In the meantime, grind up the rolled oats (if you aren't using oat flour) in your blender. Then, add the baking powder, cinnamon, and salt in with the oat flour and pulse to combine. Empty the dry mixture into a bowl from your blender, then set aside.
Add all wet ingredients for the waffles into the bottom of your blender, then add the dry ingredients over top. Blend until you achieve a smooth batter consistency. It should be thick, but still pourable.
Fold in chocolate chips at this point if you are using them. Set the batter aside while you preheat your waffle iron on medium.
Once heated, lightly oil the waffle iron with coconut oil or vegan butter (unless you have a non-stick one). Ladle batter evenly onto waffle iron, adjusting as needed for different sized irons. Cook for 4-5 minutes until slightly crispy and golden brown.
You can keep the cooked waffles warm by storing them on a wire rack in your oven set to 200°F. Just don't stack the waffles once they are cooked to prevent them from turning soggy.
While the waffles are cooking, blend the blueberry mixture together until you achieve a smooth, syrup consistency. Keep it in the fridge until you are ready to serve.
Serve waffles with vegan butter, nut butter, blueberry syrup, banana slices, or any other fruit you love!