Place an oven rack in the center of the oven. Preheat the oven to 375 degrees F.
Spray a 9 by 5-inch loaf pan with cooking spray.
In a large bowl, stir together the bread crumbs, parsley, sun-dried tomatoes, garlic, if using, eggs, milk, feta, salt, and pepper. Add the turkey and gently stir to combine, being careful not to overwork the meat.
Carefully pack the meat mixture into the prepared pan and bake until the internal temperature registers 165 degrees F on an instant-read thermometer, about 45 minutes. Remove from the oven and let rest for 5 minutes. Transfer to a cutting board and slice. Put on a serving platter and serve.
Recipe courtesy Giada De Laurentiis