Creamy Beef Mushroom Barley Soup in a Slow Cooker
- Cook and stir ground beef in a large skillet over medium heat until crumbly, evenly browned, and no longer pink, 7 to 10 minutes. Drain excess grease, and transfer beef to a slow cooker.
- Place shiitake mushrooms into a food processor and pulse several times to cut the mushrooms into small pieces.
- Stir shiitake mushrooms, beef broth, barley, sweet onion, garlic, black pepper, salt, celery seed, and parsley with the ground beef in the slow cooker.
- Cook on Low for 5 hours.
- Stir heavy cream and green beans into the soup and cook 1 hour more.