Preheat oven to 350 degrees F. Thoroughly coat a large baking sheet with cooking spray.
In a large bowl, combine ground turkey, grated onion, garlic, sun-dried tomatoes, mozzarella, basil, parsley, oregano, egg, breadcrumbs, salt and pepper.
Mix well to combine. Using a 2 tablespoon portion of the turkey mixture, form meatballs by rolling between the palms of your hands. Place the meatballs on the prepared baking sheet, spacing evenly.
Bake until the meatballs are firm to the touch and cooked through, about 15 minutes.
Brush the meatballs liberally with the basil pesto. Return to the oven for 5 minutes. Serve immediately.
These can be served over rice or pasta as an entree, or as hors d'oeuvres. The meatballs can be mixed and rolled several hours in advance. Cover and refrigerate. Remove from the refrigerator and uncover before baking.