Preheat oven to 400°F. Line a baking tray with parchment paper and set aside.
In a medium mixing bowl, combine breadcrumbs, milk, egg, onion, and seasoning. Add in beef and parmesan cheese and combine until just mixed through, being careful not to overmix.
Using a 1 ½ Tablespoon cookie scoop (or a spoon), make 48-60 meatballs. Gently roll in your palms to create round balls. Lay the meatballs about an inch apart on baking tray.
Bake the meatballs for 15-18 minutes or until meatballs reach an internal temperature of 160°F.
Notes
Makes about 4 dozen meatballs.Leftover meatballs can be stored in an airtight container in the fridge for up to 4 days. Or, meatballs can be frozen in a zip-top bag in the freezer for up to 3 months.