Preheat oven to 425°F. Line a sheet pan with parchment paper.
To a medium bowl add egg, milk, bread crumbs, and olive oil. Mix together with a whisk. Let mixture sit while you prepare other ingredients (onions, garlic, parsley, etc.), about 5 minutes. The breadcrumbs will absorb the wet ingredients which helps the meatballs stick together.
Add meat, onion, parsley, garlic, salt, and pepper to the bowl. Gently mix together with your hands until well combined.
Use a cookie scoop to divide the meat into 24 equal portions, about 2 tbsp each.
Gently form each portion into a ball. Place meatballs on a parchment paper-lined pan, evenly spaced.
Bake for 12-15 minutes or until internal temperature reaches 165°F and the outsides are golden brown.
If you'd like to brown your meatballs a little more, you can broil them on high for 3-5 minutes after the initial cooking time.
