Preheat oven. Line a baking sheet with parchment paper and spray with cooking spray. Set aside.
In bowl, combine ground meats, breadcrumbs, egg, onion, parsley, salt, and pepper. Mix thoroughly.
Shape the mixture into balls and place them on the prepared baking sheet. Bake until no longer pink inside.
Turn on the broiler. Place the pan of meatballs and broil until brown and crisp.