Portabella Mushroom Sandwiches With Roasted Garlic Basil Mayo

This sounds sooooo good. I found it in the bon appetit magazine and can't wait to try it. If you get to it first, let me know what you think. The preparation time has not been added because I've yet to make this, and I've guesstimated the time needed to cook.

• Ready In: 35 mins
• Serves: 6

Ingredients

• 2  garlic cloves, unpeeled
•  olive oil (for drizzling)
• 1  cup mayonnaise
• 1⁄3 cup basil leaves, fresh minced
• 1  teaspoon  balsamic vinegar
• 3  tablespoons  balsamic vinegar
• 6  tablespoons butter, divided (3/4 stick)
• 1  lb portabella mushroom, stems trimmed and cut into 1/4-inch slices (about 5 large)
• 1  lb  bread, halved horizontally (pain rustique, ciabatta or facaccia)
• 1⁄3 cup parmesan cheese, freshly grated
• 1  large tomatoes, thinly sliced

Directions

1. Preheat oven to 400 degrees.
2. Place garlic in small ovenproof dish and drizzle with olive oil and sprinkle with salt and pepper.
3. Cover tightly with foil and roast until tender, about 30 minutes.
4. Cool, peel and mash garlic.
5. Mix mayonnaise, basil, 1 teaspoon balsamic vinegar and mashed roasted garlic in small bowl. Do ahead Can be made1 day ahead. Cover and chill.
6. Melt 4 tablespoons butter in large skillet over medium-high heat.
7. Add mushrooms and toss to coat.
8. Drizzle remaining 3 tablespoons balsamic vinegar over and cook until tender, stirring often, about 5 minutes.
9. Season with salt and pepper. This step can be made 2 hours ahead of time. Let stand at room temperature.
10. Rewarm over low heat before continuing.
11. Preheat broiler.
12. Spread remaining 2 tablespoons butter over cut sides of bread.
13. Broil bread, buttered side up, until golden brown, about 2 minutes. Watch closelyto prevent burning.
14. Spread desired amount of garlic-basil mayonnaise over toasted sides of bread.
15. Arrange mushrooms in even layer over bottom half of bread.
16. Springles Parmesan cheese over.
17. Arrange tomato slices in single layer over cheese.
18. Cover with top half of bread.
19. Cut into 6 sandwiches and serve.