Combine, artichokes, celery, peppers, capers, Muffaletta Mix and olive oil in a small bowl. Stir to combine. Season to taste with vinegar, salt, and pepper.
Tear out some of the doughy insides of the bread if it’s especially thick, and lay bread slices down face up on cutting board. Spoon olive mixture on both top and bottom halves. Layer meat, cheese and lettuce onto bottom half, then top with top half. Cut into quarters and serve immediately, or for better flavor, wrap in plastic and allow bread to soak up juices for one hour before serving.