Portobello Sandwich

Slice off the top third of the bread loaf and set aside.

Pull out center of bottom portion of bread loaf with your hands, leaving a 1-inch shell around the outer edges and bottom. Set aside hollowed-out bread loaf, and reserve the center for another use, if desired. Preheat broiler.

In a small bowl, combine vinegar, mustard, oil, sugar, salt and pepper, and whisk until smooth. Brush HALF of this mustard mixture evenly over tops of mushrooms.

Broil mushrooms about 4-inches from heat until lightly browned, about 5 minutes.

Brush remaining mustard mixture over inside of hollowed-out bread loaf. Layer lettuce on bottom and up the sides of the loaf. Layer evenly with sun-dried tomatoes, mushrooms, onion, tomato, and cheese. Broil this portion of the bread until cheese melts on top, about 5 minutes or until cheese melts.

Top filled loaf with reserved top crust, pressing down firmly with hands. Cut into wedges to serve.