Make Oat Flour: In a blender, process oats into a fine flour. Just blend for about 30 seconds until the oats turn into flour. (I don't every buy oat flour because it is expensive and you can so easily do it yourself)
Add the rest of the ingredients: To the blender with the oats, add the almond flour, flax seeds, cinnamon, vanilla, baking soda, baking powder, eggs, and milk.
Blend the batter: Put the lid on the blender, and start at low speed. Once the blender is on, slowly turn up the speed to blend the batter until there are no more clumps. You may need to scrape down the sides halfway through if it is sticking.
Cook the Waffles: Preheat and grease your waffle iron (I like to use coconut oil). Pour in batter and cook until golden and crisp (about 3–5 minutes). The amount of batter you use will depend on the size of your waffle iron. I have a standard sized round waffle iron, and I use a 1/3 cup measuring cup to pour in the batter.
Cool & Freeze: Cool waffles completely. Freeze in a single layer by arranging them on a baking sheet, then transfer to a freezer bag or container to store.