Blend all ingredients (except optional sesame seeds, which we'll use later) in a high speed blender until smooth. (I use Vitamix.)
Heat up your waffle iron as per manufacturer's instructions. If you are going for a completely oil-free waffle (and you don't have a brand new non-stick waffle iron), you're going to want to sprinkle a few sesame seeds on the lower portion of your waffle iron before pouring on the batter. Now, pour on your batter. Sprinkle a few more pinches of sesame seeds on the top of your batter before pulling down your iron lid.
Cook waffle according to your waffle iron's instructions, but I wouldn't trust your waffle iron if it beeps that this waffle is done before 6 minutes. With my Cuisinart waffle iron, this waffle needed to cook at least 8-10 minutes before it was done. Remember, with all the oats and flax in there, you're going to want to cook it a little bit longer to prevent goopiness, for lack of a better term.
Serve up your waffles hot with your favorite fruit sauce!