5 garlic cloves, unpeeled
7 tablespoons olive oil
1 tablespoon fresh lemon juice
1 tablespoon minced fresh rosemary
2 teaspoons Dijon mustard
½ cup mayonnaise
2 tablespoons sugar
2 tablespoons balsamic vinegar
4 (4- to 5-inch-diameter) Portobello mushrooms, cleaned & stems removed
1 red onion, cut into four ¼ to ½ inch slices
4 sections good baguette or Ciabatta rolls, halved
1 cup baby arugula or peppery sprouts
1. Preheat oven to 350o.
2. Place garlic in small baking dish. Drizzle with 1 tablespoon oil; toss to coat. Cover dish with foil and bake until garlic is tender; about 20 minutes.
3. Cool garlic slightly. Peel.
4. Combine roasted garlic, 1 tablespoon oil, lemon juice, rosemary and mustard in mini-processor. Blend well scraping down sides of processor occasionally.
5. Transfer mixture to small bowl. Whisk in mayonnaise.
6. Season aloli with salt and pepper. Set aside.
7. Prepare grill (medium heat) or preheat broiler.
8. Stir sugar and balsamic vinegar in heavy small saucepan over medium heat until sugar dissolves.
9. Simmer mixture until syrupy and reduced slightly. Cover; keep warm.
10. Brush mushroom caps and onion slices on both sides with 3 tablespoons oil. Sprinkle with salt and pepper. Grill or broil mushrooms and onions until tender and cooked through, about 4 minutes per side. Transfer to platter; cover with foil to keep warm.
11. Brush cut sides of bread with remaining 2 tablespoons oil. Grill or broil bread cut sides toward heat, until lightly toasted, about 2 minutes.
12. Spread 1 tablespoon aioli over cut side of each roll bottom.
13. Top each with ¼ cup of arugula or sprouts, then 1 mushroom cap and 1 slice of onion.
14. Drizzle a bit of balsamic syrup over onion on each roll.
15. Spread 1 tablespoon aloli over top half of each roll. Place atop sandwiches and serve.