1Trim excess fat from beef. Heat nonstick Dutch oven over medium heat. Cook beef in Dutch oven until brown on all sides; drain. Place onion on beef.
2In small bowl, mix reserved pineapple juice, the soy sauce, ginger and garlic; pour over beef. Heat to boiling; reduce heat. Cover; simmer about 2 hours or until meat is tender.
3Add celery. Cover; simmer 20 minutes. Add pineapple, spinach and mushrooms. Cover; simmer 5 minutes longer. Remove beef, pineapple and vegetables. Skim any fat from broth. Serve broth with beef, pineapple and vegetables.