Bring the water and rice to a boil in a medium saucepan over high heat, uncovered. Reduce the heat to low, then cover and simmer for 50 minutes. Remove from the heat and let stand for 10 minutes with the lid still on.
Add to a large bowl: the cooked rice, beans, oats, onion, mushrooms, tomato paste or ketchup, garlic, oregano, chili powder, granulated onion, cumin, and basil. Stir until the ingredients are evenly mixed.
Split burger mix into two batches, add half to the food processor and pulse a few times, just until everything sticks together. Repeat with the second batch. Combine both batches together.
Shape the mixture into patties 3-4 inches wide and about ½ inch thick. Preheat a nonstick frying pan over medium heat. Depending on the size of your pan, cook 2 to 4 patties at a time, cooking each side for 5 to 8 minutes or until browned. If you don’t want to use a nonstick pan you can bake on baking sheets lined with parchment paper at 400 degrees for 10 minutes.
Serve on romaine lettuce leaves with traditional burger toppings, such as tomato, avocado, onions, ketchup and/or mustard