Mighty Hero Sandwich

Ingredients

• 1/4 cup balsamic vinegar
• 1 tablespoon minced fresh parsley
• 1 tablespoon olive oil
• 2 garlic cloves, minced
• 1/4 teaspoon dried oregano
• 1/4 teaspoon pepper
• 1 large tomato, halved and sliced
• 1 cup sliced fresh mushrooms
• 2 thin slices red onion, separated into rings
• 1 round loaf (1 pound) sourdough bread
• 1 small zucchini, shredded
• 1/2 pound sliced deli turkey
• 6 slices part-skim mozzarella cheese