Place the ground beef, breadcrumbs, parmesan cheese, egg, milk, garlic, onion powder, basil, salt and pepper in a large bowl and mix together gently just until combined. Do not over work the meat or the meatballs will be dense.
Form the meatballs into 1 1/2" balls and place on a baking sheet.
Place as many meatballs on the plate of your air fryer without overcrowding (you will more than likely need to cook (2) batches).
Cook at 390 degrees for about 10 minutes or until a thermometer inserted into the center registers 165 degrees. All air fryers vary, so begin checking for doneness after 8 minutes of cooking time. Remove from heat and garnish with fresh parsley if desired. Enjoy!
Notes
Pro tip: Prep meatballs 1-2 days in advance, or freeze them.To freeze: Freeze in a single layer, then transfer to a zip top bag. Air fry from frozen, adding 2-5 minutes extra to the cooking time or until a thermometer inserted into the center registers 165 degrees.
Change things up by using ground pork, or a combination of beef and pork.
Store leftover air fried meatballs in the refrigerator for up to 3 days.
Serve as a main dish with marinara or bbq sauce, or serve as an appetizer with your favorite dipping sauce.