Heat the oven to 400°F. Line a large rimmed baking sheet with oven-safe parchment. Brush it with half the olive oil.

Combine the panko and milk in a large bowl. Let stand for 5 minutes while you mince the garlic and chop the parsley.

Stir the egg, Parmesan, garlic, parsley, salt, and pepper into the soaked crumbs. Add the cold turkey and mix gently just until evenly combined.

Divide into 16 equal portions and gently roll into balls, roughly 1 1/2 inches across. Arrange with space between them and lightly brush the tops with the remaining oil. Wash hands and clean surfaces that contacted raw poultry.

Bake for about 18–22 minutes, checking early if your meatballs are smaller. Insert a thermometer into the center of several, including the largest; every checked meatball must reach at least 165°F. Continue baking as needed.

Serve four meatballs per person with your chosen sides. Refrigerate leftovers in shallow containers within 2 hours, or 1 hour above 90°F. Use within 3–4 days and reheat to 165°F.