In food processor, mix walnuts, onion and crackers. Pulse until coarsely crumbed. Pour into large bowl.
Now in processor mix eggs and creamed cheese until smooth.
Mix egg mixture into walnut mixture in bowl. Add cheddar and oregano, blend well. If mixture is too loose, add more cracker crumbs.
Heat 2 T vegetable oil in nonstick skillet on medium. Drop mixture into patties in hot nonstick skillet. Drain on paper towels after browned and firm. (Watch closely, they can burn easily).
Mix sauce ingredients together with a whisk. Spray 9" X 13" casserole dish with oil spray. Layer patties in a single layer in bottom of dish. Pour 3/4 sauce over patties. Bake uncovered for 20 minutes, pour rest of sauce on, and bake 10 minutes more. Serve with green salad on the side.