Heat oven to 350 degrees F.
In lg.bowl, combine meatloaf ingredients, mixing lightly but thoroughly.
In medium bowl, combine filling ingredients; mix well.
Set aside.Place beef mixture on waxed paper and pat into 14 x 10 inch rectangle.
Spread filling over beef, leaving 3/4 inch border around edges.
Starting at short end, roll up jelly roll fashion.
Press beef mixture over spinach filling at both ends to seal.
Place seam side down on rack in open roasting pan.
Bake in 350 degrees F oven 1 hour.
Spread ketchup over loaf; return to oven and continue baking 15 minutes.
Top loaf with 1/4 cup mozzarella cheese.
Sprinkle with additional Italian seasoning, if desired.
To serve, cut into 1 inch thick slices.
Cook's Tip: To make soft bread crumbs, place torn bread slices in food processor, fitted with steel blade, or blender container.
Cover; process 30 seconds, pulsing on and off, until fine crumbs.
One and a half slices will yield 1 cup of soft bread crumbs.