Bobby's Lighter Green Bean Casserole

Preheat the oven to 350 °. Spray a 1 1/2 quart baking dish with nonstick spray. Bring a large pot of water to a boil. Add the beans and cook, stirring occasionally, until the beans are tender, about 6 minutes. Drain. Heat the oil in a large nonstick skillet. Add the mushrooms, onion and seasoning. Cook, stirring occasionally, until the mushrooms and onion are very tender, about 8 minutes. Remove from the heat. Stir in the cooked beans, soup, milk, 1/4 cup onion rings and 1/4 cup cheese; toss to mix well. Spoon the mixture into the baking dish. Top with the remaining 1/4 cup onion rings and 1/4 cup cheese. Bake, uncovered, until the filling is hot and bubbly, about 25 minutes.