1) In 2 tablespoon olive oil, saute onion and mushroom until onion starts to brown. Mix with all other ingredients, if you would like to bake these in the oven, mix in remaining olive oil as well.
2) Shape into 6 patties and fry in olive oil until brown on both sides. If baking, place patties on greased cookie sheet, and bake at 350 degrees Fahrenheit for 20 min, then flip and cook for 10 more minutes.
3) Serve on hamburger buns with your favorite veggies & condiments. These are also good frozen and reheated on a charcoal grill.
Source of recipe: I've experimented on my family for weeks developing this recipe. It can also be fried without shaping and used as "meat" crumbles, for taco filling or pizza topping, or any other ground meat use.