Preheat and prep: Heat oven to 400°F (200°C). Line a sheet pan with parchment paper or lightly oil it.
Grate the onion: Using the fine holes of a grater, grate the onion.
Squeeze gently to remove excess moisture so the mixture isn’t wet.
Mix the base: In a large bowl, add turkey, grated onion, garlic, egg, breadcrumbs, feta, parsley, dill, mint (if using), oregano, salt, pepper, lemon zest, and 1 tablespoon olive oil.
Combine gently: Use a fork or your hands to mix just until combined. Don’t overwork the meat or it will get dense.
Shape: Scoop about 2 tablespoons per meatball and roll lightly with damp hands. Place on the prepared pan, spacing evenly.
Brush and bake: Brush the tops with the remaining 1 tablespoon olive oil.
Bake 14–18 minutes, until the centers reach 165°F (74°C).
Optional broil: For color, broil 1–2 minutes at the end. Watch closely to avoid burning.
Rest and serve: Let them rest 3–5 minutes. Serve with tzatziki or Greek yogurt, lemon wedges, and your favorite sides.