In a medium sized bowl combine the ground beef, onion, garlic, parmesan cheese, breadcrumbs, parsley, salt, pepper, egg and milk.: You will notice the mixture has a cool, slightly tacky feel as the milk and egg hydrate the breadcrumbs, and the aroma of garlic and onion will be apparent even before cooking. Mixing by hand allows you to feel for even distribution without overworking, which keeps the texture tender. Use gentle folding motions, turning the mixture over rather than kneading, until ingredients appear uniformly combined. A common mistake is to compact the meat through excessive handling, which creates tight, dense meatballs, so stop as soon as everything is incorporated. If the mixture seems too loose, chill it for 10 to 15 minutes, which firms the fats and makes shaping easier. You'll want to avoid leaving raw meat at room temperature for too long, so proceed to shaping promptly after mixing.
Shape into 2-inch sized meatballs. Place in the basket of your air fryer in an even layer.: As you form each ball, press lightly to round instead of compressing, and you'll notice the mix holds together with a slightly springy texture. The size determines cook time and internal juiciness, and 2-inch meatballs offer a satisfying balance between crisp exterior and tender interior. Arrange them in a single layer with some space between each so hot air can circulate freely, which creates even browning. If you crowd the basket, steam will form and prevent a golden crust, so work in batches if needed. During shaping, a common slip is inconsistent sizing, which results in mixed doneness; a small kitchen scale or measuring spoon helps keep them uniform. If you prefer a smoother surface, lightly wet your hands before rolling to reduce sticking and encourage a glossy outer texture.
Cook at 400 degrees for 10-12 minutes or until cooked throughout.: When you start cooking, the first few minutes will deliver a burst of sizzling sound and a whiff of roasted garlic and parmesan cheese . The air fryer’s high heat quickly forms a brown, slightly crisp exterior while sealing juices inside. Check for visual cues like an even golden color and slight firmness when pressed; if using an instant read thermometer aim for a safe internal temperature indicating doneness. Flip halfway through the cooking window to promote even browning on all sides. Avoid opening the basket frequently, as heat loss can lengthen the cook time and prevent the crust from forming. One error to steer clear of is relying solely on color for doneness, which can be deceptive; always test a center if you are unsure. After cooking, let the meatballs rest briefly, which allows juices to redistribute and prevents them from drying out when cut or served.
