Creating Slow Cooker Salisbury Steak Meatballs is simple if you follow these easy steps:

1. Mix Meatball Ingredients: In a large bowl, combine ground beef, bread crumbs, chopped onion, egg, garlic powder, onion powder, Worcestershire sauce, salt, and pepper. Mix until fully combined.
2. Form Meatballs: Shape the mixture into medium-sized meatballs, about 1-2 inches in diameter.
3. Place Meatballs in Slow Cooker: Arrange the meatballs in the bottom of the slow cooker.
4. Prepare Gravy: In a separate bowl, mix the beef broth, sliced mushrooms, and remaining seasoning to create the gravy.
5. Pour Gravy over Meatballs: Carefully pour the gravy mixture over the meatballs in the slow cooker.
6. Set Cooking Time: Cover the slow cooker and set it to cook on low for 6-8 hours or high for 3-4 hours.
7. Thicken Gravy: If you prefer a thicker gravy, whisk together heavy cream and cornstarch in a small bowl, then stir it into the slow cooker 30 minutes before serving.
8. Check for Doneness: Ensure the meatballs are cooked through and the gravy is rich and velvety.
9. Serve Warm: Once cooked, ladle meatballs and gravy onto plates.

By following these steps, you will have a fantastic meal that will please everyone at the table!