Preheat the oven to 400°F. Line a baking sheet with foil and spray with non-stick cooking spray.
In a large bowl, combine the meat, egg, breadcrumbs, cheese, onion, garlic, salt, pepper, and parsley, if using.
Use a medium cookie scoop or spoon to scoop the meat mixture. Form into 1 ½-inch balls and place on the baking sheet.
Bake uncovered 17 to 20 minutes, or until no longer pink in the middle. Turn halfway through, so the bottoms don't brown.