01 - Preheat oven to 400°F. Line a rimmed baking sheet with parchment paper or lightly coat with olive oil.
02 - In a large mixing bowl, combine the ground turkey, basil pesto, grated Parmesan, breadcrumbs, egg, minced garlic, grated onion, kosher salt, and black pepper. Mix gently with your hands or a fork just until all ingredients are evenly distributed — do not overwork the mixture or the meatballs will become dense.
03 - Using damp hands or a 1½-inch cookie scoop, portion the mixture and roll into 16 to 18 uniform meatballs. Arrange them on the prepared baking sheet, spacing about 1 inch apart.
04 - Lightly drizzle or brush the tops of each meatball with olive oil to promote even browning and a golden crust during baking.
05 - Bake on the center rack for 18 to 20 minutes, until the meatballs are lightly browned on the outside and the internal temperature registers 165°F when checked with an instant-read thermometer.
06 - Transfer the meatballs to a serving platter. Garnish with spoonfuls of extra pesto, torn fresh basil leaves, and an additional sprinkle of grated Parmesan if desired. Serve warm.