Heat oven to 350 degrees. Line a sheet pan with parchment paper and coat with cooking spray.
Prepare the meatloaf: In a large bowl, beat the egg. Add ground turkey, apple, onion, panko, Worcestershire, garlic powder, salt, pepper and Italian seasoning, if using. Using hands, combine until everything is well mixed. Transfer to the prepared sheet pan and form into a football-shaped loaf, about 9-by-5 inches.
Make the sauce: In a small bowl, mix ketchup, brown sugar, vinegar, Worcestershire and pepper until well combined. Pour evenly over the top of the meatloaf, allowing the sauce to drip down the sides.
Bake meatloaf until the temperature in the center registers 160 degrees on an instant-read thermometer, 45 to 55 minutes. Let rest for 10 minutes before slicing.
