- Stir beef stock, tomato sauce, water, onion, carrot, barley, mushrooms, and garlic together in a slow cooker.
- Season beef chunks with garlic salt, salt, and black pepper; add to the beef stock mixture. Add bay leaves to the slow cooker.
- Cook on Low until the soup thickens and the beef is tender, about 6 hours.
- Remove and discard the bay leaves to serve.
Note:
If you have time you can brown the beef, but it's just as good without the beef browned because the slow cooker makes the beef very tender.