Prep: 7 minutes; Cook: 11 minutes
1. Preheat broiler.
2. Place mushrooms on a baking sheet; coat evenly with balsamic spritzer. Broil mushrooms 11 to 12 minutes or until browned and tender.
3. While mushrooms broil, spread 1 tablespoon Parmesan Mayonnaise over cut side of each bread slice; top each of 4 slices with about 2/3 cup bell pepper and 1/2 cup arugula. Arrange roasted mushrooms evenly over arugula. Top with remaining 4 bread slices.