Combine soup, cream cheese, minced onion, water, and milk in a saucepan and simmer until creamy; set aside. Boil broken spaghetti for 7 minutes and drain.
Dice spam and place in 9x13-inch baking dish or cake pan. Cover with spaghetti and mushroom soup mixture, sprinkle with Parmesan cheese, add mushrooms, bread crumbs and top with mozzarella cheese.
Bake uncovered at 400°F for 20-30 minutes.
Submitted by: Bre Thompson