Preheat the oven to 400℉. Line a baking sheet with unbleached parchment paper and pray it with avocado oil spray or drizzle it with avocado oil and smear it over the parchment.
Grate the onion and mince the garlic. Next, in a large bowl, add the beef, eggs, milk, Worcestershire , Pecorino Romano, dry oregano, salt and pepper. Combine well.
Roll the meatball mixture into the size of golf balls and place them on the parchment lined baking sheet. Spray the meatball with avocado oil spray (or drizzle with avocado oil).
Bake for 20- 25 minutes until the meatballs are fully cooked through.