Preheat and prep: Heat your oven to 425°F (220°C).
Line a rimmed sheet pan with parchment and lightly oil it so the meatballs brown and don’t stick.
Mince and grate: Finely mince the garlic and herbs. Grate the onion on the small holes of a box grater. The grated onion adds moisture and blends right into the meat.
Mix the binder: In a large bowl, whisk the egg, Greek yogurt, olive oil, Parmesan, salt, pepper, oregano, and red pepper flakes.
Stir in garlic, onion, parsley, basil, and lemon zest.
Add turkey and breadcrumbs: Add the ground turkey and breadcrumbs to the bowl. Gently fold everything together with a fork or your hands until just combined. Do not overmix or the meatballs will be tough.
Shape: Lightly oil your hands. Scoop and roll into 1.5-inch balls (about 20–24 meatballs).
Place them evenly on the prepared pan with a little space between each.
Bake: Bake for 12–14 minutes until mostly cooked through. For a golden top, switch to broil for 2–3 minutes, watching closely. Internal temperature should reach 165°F (74°C).
Rest and serve: Let the meatballs rest 5 minutes to reabsorb juices.
Serve with warm marinara, over zucchini noodles, tucked in a pita with greens and tzatziki, or alongside roasted veggies and rice.