Remove stems from mushrooms; discard stems. Remove brown gills from the undersides of mushrooms using a sharp knife; discard gills. Place mushrooms and eggplant on a broiler pan; brush vegetables with 1 tablespoon vinaigrette. Broil 6 minutes. Turn vegetables over; brush with 1 tablespoon vinaigrette. Broil for an additional 5 minutes or until tender. Combine bell peppers and basil. Spoon 1 tablespoon pepper mixture over each eggplant slice. Top each mushroom with 1 cheese slice. Broil for 1 minute or until cheese melts. Brush 2 tablespoons vinaigrette evenly over the cut sides of rolls. Arrange the spinach evenly on bottom halves of rolls. Top each roll half with 1 mushroom and 1 eggplant slice; cover with roll tops.