Beat the egg in a large bowl. Add the panko breadcrumbs, egg, milk, parsley, garlic and the seasoning and stir to combine. Add the ground beef and mix again to combine. Form into 16 meatballs and set on a plate.
Transfer the meatballs to the air fryer and arrange in a single layer. You may need to cook in two batches. Cook until the meatballs are browned and the internal temperature of the beef reaches 160°F, shaking the basket halfway through, 8-10 minutes total.
Allow the meatballs to rest for 5 minutes before serving with marinara sauce, if desired.
Notes
*Nutrition label for meatballs only.To store: Keep leftover meatballs in an airtight container or zip-top bag in the refrigerator.To reheat: Add them to a preheated 250°F air fryer and heat for about 5 minutes or until warmed through. Alternatively, heat it in a skillet, oven, or microwave.To freeze uncooked meatballs: Once you form the meatballs, line a sheet pan with parchment or wax paper and freeze until solid. Then, transfer them to a freezer-safe bag or container and store up 3 months.