Preheat the air fryer. Set it to 375°F (190°C) for 3–5 minutes. A hot basket helps form a nice crust.
Mix the meat. In a large bowl, combine ground beef, ground pork, egg yolks, salt, and any optional seasonings. Use your hands and mix just until combined. Do not overwork or the meatballs may turn dense.
Shape the meatballs. Scoop about 2 tablespoons per meatball and roll gently.
Aim for 14–16 meatballs. Lightly wet your hands to prevent sticking.
Grease the basket. Brush or rub the air fryer basket with tallow, ghee, or butter to minimize sticking and add flavor.
Arrange in a single layer. Place meatballs in the basket with a little room between each. Work in batches if needed so they crisp properly.
Air fry. Cook for 8–10 minutes at 375°F (190°C).
Shake the basket or turn the meatballs halfway through for even browning.
Check doneness. Internal temperature should reach 160°F (71°C) for beef/pork. If not there yet, cook 2–3 minutes more.
Rest briefly. Let meatballs sit for 3 minutes to reabsorb juices before serving.
Optional finish. Toss hot meatballs with a small spoon of melted tallow or butter for extra gloss and richness.