Finely grate the onion and the garlic (Note 2). Place them in a bowl.
Meatball mixture: Add ground turkey, breadcrumbs, egg, Parmesan, sweet and smoked paprika, chopped fresh herbs or dried herbs, salt, and pepper, and combine. Don’t overmix.
Form about 30 meatballs, slightly smaller than a golf ball; each should weigh about 1 oz/ 30 g. Lightly wet your hands several times while forming the meatballs.
Preheat the air fryer to 400°F (200C). Spray the basket with cooking spray.
Arrange the meatballs in the basket in a single layer; you will probably have to cook them in two batches. Spray them with cooking spray as well.
Air fry the meatballs: Cook them for 6 to 8 minutes, flipping them or shaking the basket halfway through.
Check that they are cooked through; the internal temperature should be 165°F (74°C). Or break one in the middle to see if it’s fully cooked inside.
Notes
I love using fresh or frozen dill for meatballs, but parsley or other herbs are also great. Sub with 1 teaspoon dried thyme, oregano, or marjoram if you like.
Grating ensures that you will not bite on onion pieces; the cooking time is short, and they will not be able to soften properly if not grated. Alternatively, you can cook the onions in a pan until soft, but that takes longer, and it means that you will have to clean an extra pan.