Preheat oven to 400 degrees F (200 degrees C). Prepare a baking dish with cooking spray.
Mix turkey, egg, bread crumbs, Italian seasoning, garlic, black pepper, and salt in a large bowl; shape into a loaf and put into prepared baking dish.
Bake in preheated oven for 40 minutes. Spoon about half the tomato sauce over the loaf and continue baking until the meatloaf is no longer pink in the center, 10 to 15 minutes more. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C). Rest meatloaf 5 to 10 minutes before slicing to serve.
While the meatloaf rests, warm remaining tomato sauce in a small saucepan over medium-low heat; serve with the sliced meatloaf.