Prepare the Meatballs: In a large bowl, combine the ground beef, ground pork, breadcrumbs, Parmesan cheese, egg, chopped onion, minced garlic, Worcestershire sauce, salt, and pepper. Mix until well combined but don’t overmix.

Shape the mixture into 1.5-inch meatballs and set aside.

Brown the Meatballs (Optional): Heat a skillet over medium heat and brown the meatballs on all sides. This step is optional but adds extra flavor to the meatballs.

Prepare the Gravy: In a separate bowl, whisk together the beef broth, heavy cream, Worcestershire sauce, Dijon mustard, soy sauce, and salt and pepper. If you’re using cornstarch to thicken the gravy, mix it with a little cold water to form a slurry before adding.

Place the meatballs in the slow cooker. Pour the gravy mixture over the meatballs.

Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the meatballs are cooked through and tender.

If the gravy is too thin, mix the cornstarch slurry into the slow cooker and stir well. Continue cooking for an additional 30 minutes to thicken.

Serve the Salisbury steak meatballs over mashed potatoes, rice, or a low-carb alternative such as cauliflower rice.