PreparationPlace the water in a large pot with the onion, celery, soy sauce, onion powder, and garlic powder. Bring to a boil, reduce the heat, and simmer for 5 minutes. Stir in the oats, mushrooms, and flour and cook 5 minutes longer. Transfer to a bowl and chill for at least 1 hour, preferably longer.Preheat the oven to 350°F.Shape the mixture into burger-sized patties and place on the baking sheets. Bake for 15 minutes. Remove from the oven and let rest for 5 minutes. Carefully flip over and bake 10 more minutes.Before serving, place the baked patties on a nonstick griddle and grill for about 7 minutes on each side, until browned. Serve on buns with topping of your choice. From The Healthiest Diet on the Planet © 2016 by Dr. John McDougall. Reprinted with permission by HarperOne, an imprint of HarperCollins Publishers. Buy the full book from HarperCollins or from Amazon.