Combine all ingredients, except cheese ... onions. Pour into casserole. Bake, uncovered, at 350 ... remaining cheese and onions. Bake 5 minutes longer.
Cook mushrooms and onions in ... into large greased casserole. Bake at 350 degrees ... refrigerated, allowing 30-40 minutes to heat through. Serves 8-12.
Ingredients: 13 (flour .. salt .. sauce .. style ...)