Combine the ground beef, panko, cheese, egg, milk, chopped onion, minced garlic, parsley, salt, pepper, paprika, and oregano in a large bowl. Mix everything together with your hands until just combined—don't overmix or they'll get tough. I usually mix for about 30 seconds until everything is evenly distributed but still kinda loose looking.

Roll the mixture into 16 to 20 balls about the size of walnuts, which makes them cook evenly in the meatball recipe without drying out. If they're too big they won't cook through in 12 minutes, and too small means they'll burn on the outside. Wet your hands slightly so the mixture doesn't stick to your fingers and make rolling faster.

Brush the air fryer basket with the olive oil to prevent sticking and make cleanup way easier. Arrange your meatballs in a single layer without touching each other—they need space for air to circulate around each one. Don't try to stack them or cram too many in because they won't get that crispy exterior.

Set your air fryer to 400°F and cook for 12 minutes, shaking the basket halfway through at the 6-minute mark. The first time I made these I didn't shake them and some got more golden than others. That shake at the midpoint is what makes them cook evenly on all sides.

Check for doneness by cutting the biggest meatball in half—the inside should reach at least 160°F and have no pink remaining. If they need a bit more time, shake the basket and pop them back in for 2 more minutes. Mine usually hit perfect doneness right at the 12-minute mark, but every air fryer runs slightly different so adjust accordingly.

Let the meatballs cool in the basket for 2 to 3 minutes before transferring them to a serving platter or storage container. They'll continue cooking slightly from residual heat, so don't panic if they feel a tiny bit soft when you first pull them out. They firm up as they cool and that's exactly what you want.

Serve your air fryer meatballs immediately with marinara sauce, ranch dip, or your favorite dipping sauce for a crowd-pleaser appetizer. You can also toss them with pasta, throw them in a sub sandwich, or stack them into sliders for different meal options. Store leftovers in an airtight container for up to 4 days in the fridge.