Blend the dry ingredients together in a blender: oats, baking powder, flax seed, and salt. Blend until the oats are fine like coarse flour.
Pour the dry ingredients into a large bowl. (Do not think you can add the wet ingredients to the blender, it will be too thick!)
Add the water and vanilla to the bowl and stir until just combined.
Pour batter into your waffle maker. You may need to grease it depending on how non-stick your waffle maker is. Be sure to cook for a long time, otherwise they will be gummy inside. When thoroughly cooked and slightly cooled down, they are fluffy inside!
Enjoy with your favorite toppings, or freeze for later.
To Freeze the Waffles
Separate them and let them cool completely. Freeze flat on a baking sheet or cooling rack, and once frozen, put them in a closed bag. This prevents them from freezing in a big clump. To eat, put a frozen waffle in the toaster. Top with syrup, jam, chopped fruit, berries, bananas, applesauce, peanut butter, or whatever else you like.