(7-ounce) package spaghetti
2 pounds ground chuck
1 small onion, chopped
1 (26-ounce) jar spaghetti sauce
2 cups shredded mozzarella cheese, divided
2 cups shredded Cheddar cheese, divided
1 can cream of mushroom soup
Cook spaghetti according to package directions; drain and set aside. In a skillet over medium-high heat, cook beef and onion together until meat is browned and onion is tender; drain. Blend spaghetti sauce into meat. In a greased 9- by 13-inch dish, spread half of the cooked pasta. Spread half of the meat sauce over spaghetti. Sprinkle 1 cup of each of the cheeses over meat sauce. Spread mushroom soup over cheeses. Arrange remaining cooked spaghetti over top and top with remaining meat sauce. Cover and bake at 375 degrees for 30 minutes. Remove cover and sprinkle remaining cheese over casserole. Return to oven, uncovered, and bake 5 minutes longer.