Cut the bread in half lengthwise. Remove excess bread from the center of each half, leaving a boat shape with a 1/2-inch-thick shell. Place on a 10" x 15" cookie sheet and toast until golden, about 10 minutes.
Meanwhile, in a small bowl, combine the mustard and brown sugar, stirring until the sugar Is dissolved.
2Spread the mustard mixture evenly over the toasted bread shells.
Top with the ham, tomatoes, bell pepper, onion, mushrooms, drained pineapple, and mozzarella cheese.
Bake for about 20 minutes, or until heated through and the cheese is bubbly.