Place the frozen meatballs into the slow cooker.
In a mixing bowl, combine the beef broth, Worcestershire sauce, ketchup, onion soup mix, and the brown gravy mix until well blended.
Pour the prepared mixture over the meatballs in the slow cooker, ensuring an even coating. Stir gently to mix.
Cover the slow cooker with the lid and set it to cook on low heat for approximately 4 hours.
After the cooking time is complete, whisk together the cornstarch and cold water in a small bowl to create a slurry.
Add the slurry to the slow cooker and stir well. Allow the dish to cook for a few more minutes until the sauce thickens to your preferred consistency.
Serve the dish warm and enjoy!