Mix beef, pork, breadcrumbs, Parmesan, egg, milk, garlic, seasoning, salt, and pepper; form 24–32 meatballs.
Optionally, brown meatballs in a skillet.
Combine tomatoes, sauce, paste, basil, oregano, garlic powder, sugar, flakes, salt, and pepper in a slow cooker; taste and adjust.
Add meatballs; cook on low 6–8 hrs or high 3–4 hrs.
Serve in a white ceramic dish with parsley.