Spray the insert of the slow cooker with nonstick cooking spray.

Dump the frozen meatballs into the slow cooker.

In a mixing bowl, whisk together the beef broth, brown gravy mix, onion soup mix, ketchup, and Worcestershire sauce until well combined. Pour this over the frozen meatballs and stir everything together.

Cover with the lid and cook on LOW heat for 5-6 hours.

When the cook time is done, mix together the cornstarch and cold water in a small bowl with a fork. Stir the cornstarch slurry into the crockpot and allow it to cook for an additional 10 minutes or until the gravy has thickened.

Serve the Salisbury steak meatballs over egg noodles or mashed potatoes and garnish with chopped parsley.