Slow-cooker vegetable beef soup with barley is made with tender beef stew meat, chewy barley, fresh celery, chopped onions, medium carrots, and other nutritious veggies with seasoning and fresh herbs.
In a large skillet with some cooking oil, brown the mushrooms until they become golden brown. Set aside.
In the same skillet, add more oil and sear the beef chunks over medium-high heat. About 2 minutes per side.
Transfer all the ingredients to a crock pot (I used a 4.5-quart slow cooker), and season with salt and black pepper.
Cook on LOW for 6 hours or HIGH for 4 hours. Discard the bay leaves and serve right away with fresh parsley and sour cream.