Preheat the air fryer to 380°F (193°C) for 3–5 minutes.
A hot basket helps brown the meatballs quickly.
Mix the panade: In a large bowl, stir breadcrumbs with milk (or water) and let sit for 2 minutes until slightly spongy.
Build the flavor base: Add grated onion, garlic, Parmesan, parsley, Italian seasoning, salt, and pepper. Stir to combine.
Add pork and egg: Place ground pork and egg into the bowl. Gently mix with clean hands or a fork until evenly combined.
Do not overwork; stop as soon as it holds together.
Shape the meatballs: Use a tablespoon or small scoop to portion into 1–1.25-inch balls (about 18–22 meatballs). Lightly oil your hands if the mixture sticks.
Prep the basket: Spray the air fryer basket with olive oil. Arrange meatballs in a single layer with a little space between them.
Work in batches if needed.
Air fry for 9–12 minutes, shaking or turning once halfway. Cook until golden with an internal temperature of 160°F (71°C).
Rest briefly: Let meatballs sit for 2–3 minutes; carryover heat finishes cooking and keeps juices inside.
Serve: Toss with warm marinara, glaze with honey-garlic sauce, or serve plain with lemon and herbs.