First, soak the rolled oats in milk.
While soaking, saute mushrooms, with some salt over medium heat for 5 minutes, then add chopped onions and garlic and cook for next 3-4 minutes. Spice it up with soy sauce, and cook for 1 more minute. Let it cool a bit.
To the veggies add the soaked oats, quick cooking oats, parmesan cheese, egg, seasonings, flaxseed meal and mustard. Mix everything well with your hand, and place in the fridge to set for 2 hours or overnight.
Using a tablepoon scoop the mixture and shape the meatballs.
Place on a lined baking sheet and bake at 400F (200C) for 20 minutes.
Serve with my quick teriyaki sauce or any sauce you prefer.