This great flavor combo also works with leftover roast beef or pot roast.
Cut bread into quarters; cut quarters in half horizontally. Place bread quarters, cut sides up, on a baking sheet. Top each bread bottom with 2 meatloaf slices, 2 Tbsp. marinara sauce, and 1/4 cup cheese. Top each bread top with 2 Tbsp. marinara sauce and 1/4 cup cheese; sprinkle evenly with Italian seasoning.
Bake at 375° for 10 to 15 minutes or until cheese melts and meat is thoroughly heated. Top bread bottoms with bread tops, and serve sandwiches immediately.