- In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, parsley, egg, garlic powder, onion powder, salt, pepper, and Worcestershire sauce. Mix until well combined. 
- Form the mixture into meatballs, about 1.5 inches in diameter, and place them in the slow cooker. 
- In a separate bowl, whisk together the cream of mushroom soup, beef broth, soy sauce, ketchup, and thyme. Pour the mixture over the meatballs in the slow cooker. 
- Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the meatballs are cooked through and tender. 
- Serve the meatballs over mashed potatoes or egg noodles, spooning the sauce over the top.