Preheat your oven to 400°F (200°C).
In a large bowl, combine ground beef and pork.
Add breadcrumbs, Parmesan cheese, parsley, egg, garlic, salt, pepper, and milk.
Mix the ingredients thoroughly until well combined.
Shape the mixture into meatballs, about 1.5 inches in diameter.
Place the meatballs on a baking sheet lined with parchment paper.
Bake for 20-25 minutes or until browned and cooked through.
While baking, prepare your favorite marinara sauce.
Serve the meatballs with the sauce over spaghetti or on a sub roll.
Garnish with additional parsley and grated cheese if desired.