For meat loaf, combine turkey, bread crumbs, onion, tomato sauce, egg, garlic, Parmesan cheese, pepper and red pepper flakes thoroughly in a large bowl.
For filling, mix spinach and cream cheese in a separate medium bowl.
Press meat mixture into an 8 x 14-inch rectangle about 1/2-inch thick on a large sheet of waxed paper.
Spread filling over turkey, leaving a 3/4-inch border around edges.
Roll from the short end in jellyroll fashion.
Press turkey over filling at both ends and seal.
Place seam side down in open baking dish/roasting pan.
Sprinkle top with additional Parmesan cheese.
Bake 30 minutes. Spread 3/4 C tomato sauce over top until well covered, sprinkle with salt, pepper, and garlic powder. Bake another 30 minutes, until meat thermometer inserted in center of meat loaf reads 160°F.
Cut into 1-inch thick slices to serve.
Recipe Notes
Can add 1/2 C shredded mozzarella and 4 oz. cream cheese to spinach.