01 - In a large mixing bowl, combine the ground beef, ground pork, breadcrumbs, milk, egg, chopped onion, minced garlic, salt, pepper, oregano, and parsley. Mix gently until just combined, being careful not to overwork the mixture.
02 - Shape the mixture into 1½-inch meatballs and arrange them on a large plate or baking sheet.
03 - In the crockpot insert, whisk together the beef broth, cream of mushroom soup, Worcestershire sauce, Dijon mustard, onion powder, garlic powder, salt, and pepper until smooth and well blended.
04 - Carefully place the formed meatballs into the gravy mixture, nestling them so they are mostly submerged in the liquid.
05 - Cover the crockpot and cook on LOW for 6 hours or on HIGH for 3 hours, until the meatballs are cooked through and tender.
06 - In a small bowl, whisk the cornstarch and cold water together to form a smooth slurry. Stir the slurry gently into the crockpot, cover, and continue cooking on HIGH for 15 to 20 minutes until the gravy reaches your desired thickness.
07 - Serve the meatballs and gravy hot over mashed potatoes, egg noodles, or steamed rice.