Cut bread diagonally into 12 (1/4-inch-thick) slices; arrange on a baking sheet. Brush slices evenly with Italian dressing, and sprinkle with Parmesan cheese.
Bake at 375° for 5 to 6 minutes or until lightly toasted.
Spread untoasted sides of bread slices evenly with mayonnaise and mustard. Layer 4 bread slices, mayonnaise side up, with salami, mortadella, and provolone. Top with 4 bread slices, mayonnaise side up; layer with lettuce, tomato, and bacon. Top with remaining 4 bread slices, mayonnaise side down. Cut in half, and secure with wooden picks. Garnish, if desired.