Mediterranean Portobello Burger - Type 2 Nation

Ingredients

• Olive oil cooking spray
• 3 tablespoons plus 1 teaspoon bottled light balsamic or light red wine vinaigrette
• 1 clove garlic, crushed
• 2 large portobello mushrooms, stems removed
• 2 1-ounce slices mozzarella or provolone cheese
• 4 3⁄8-inch-thick slices crusty country bread (about 4½ inches round or square)
• 3 tablespoons fat-free or light mayonnaise
• 4 ¼-inch-thick slices tomato or 2 roasted red bell pepper pieces
• 4 large fresh basil leaves
• 1 thin slice red onion, separated into rings (optional)