For a richer flavor, consider using a higher fat content ground beef. Add a splash of dry sherry or white wine to the sauce for an extra layer of complexity. If you don't have cream of mushroom soup on hand, you can substitute with cream of celery or cream of chicken soup. To make this dish even more vibrant, add some sauteed mushrooms or bell peppers to the beef mixture. Leftovers can be stored in the refrigerator for up to 3 days. Reheat gently on the stovetop or in the microwave.