Grate the onion into a large mixing bowl, then add the minced garlic, parsley, dill, and lemon zest.

Add the ground turkey, egg, panko, feta, oregano, salt, and pepper. Mix gently with your hands just until everything is combined. Stop as soon as it holds together, overmixing makes the meatballs dense.

Shape the mixture into about 16 meatballs, roughly 45 to 50 g each, a little smaller than a golf ball. Place them on a sheet pan and chill for 10 to 15 minutes.

Heat 2 tablespoons of olive oil in a 12-inch nonstick skillet over medium heat.

Add half the meatballs, leaving space between each one so they brown instead of steam. Sear for 3 to 4 minutes per side, turning gently, until golden brown all over, about 8 minutes total.

Lower the heat to medium-low, cover the skillet, and cook for 5 more minutes, until an instant-read thermometer inserted in the center reads 165 F / 74 C.

Transfer the first batch to a plate and tent loosely with foil to keep warm. Add the remaining tablespoon of oil and repeat searing and covered cooking with the second batch.

Squeeze fresh lemon juice over the meatballs and serve warm with lemon wedges on the side.