In a Dutch oven, combine the beef, onions, garlic, 1/2 cup water, bouillon and enough of the broth to cover. Bring to a boil. Cover and simmer until meat is tender, about 2 hours. Add vegetables, seasonings and remaining broth. Simmer 30-45 minutes or until vegetables are tender. Combine cornstarch and water; gradually add to the boiling mixture. Cook and stir for 2 minutes.