Heat oven to 350. Line a lg rimmed baking sheet w/ foil, spray foil w/ cooking spray. In lg bowl, combine ground turkey or beef, bread crumbs, eggs, 1 cup spaghetti sauce, parmesan cheese, salt & pepper. Mix well.
Divide mix and form into 6 equal-sized patties. Place patties on baking sheet. Bake 15 mins, or until no longer pink inside. Remove patties from baking sheet.
Line baking sheet w/ more foil. Place bread halves onfoil. Place patties on the bread, 3 patties for each bread slice. Top w/ remaining sauce. Sprinkle w/ mozzarella cheese. Bake 10 mins. Slice each bread half into 3 servings each.