Set aside 8 ounces of mozzarella cheese. Finish off the top with reserved tomato sauce. Sprinkle on reserved mozzarella cheese. Bake for 45 minutes or until a knife or fork can easily be inserted in noodles. Allow firming for 15 minutes before serving.
Recipe is great for company.
Leftovers can be frozen for convenient meals later. Let stand 5 minutes, drain well and squeeze dry. Put in large bowl. Slice and hollow out centers of tomatoes. Chop pulps finely and add to spinach.