Portobello Bruschetta with Caramelized Onions

This is one of my favorite appetizers and well worth the effort. The presentation is also spectacular, a stacked vegetarian open faced sandwich.

Portobello Bruschetta with Rosemary Aioli

Serves 12

Ingredients

1 cup balsamic vinegar

2 Tb. honey

¼ cup light brown sugar

Salt and pepper, to taste

1 ½ Tb. thyme

5 portobellos, dark gills removed

8 Tb. olive oil, divided

2 small or 1 large red onion, sliced thinly

2  small red peppers

3 Tb. chopped basil

2 garlic cloves, minced

3 cups arugula, chopped

1 baguette, sliced thinly on the diagonal

Olive oil for bread

Rosemary Aioli

1/2 cup mayonnaise

2 garlic cloves, minced

1 Tb. lemon juice

2 tsp. chopped rosemary

2 tsp. Dijon mustard

Salt and pepper, to taste

Procedure

1. Heat the oven to 375. Combine the vinegar, honey, sugar, salt, pepper and thyme in a large baking dish. Reserve ½ cup of the marinade and set aside. Add the mushrooms and marinate for about 30 minutes. 
2. Meanwhile heat 2 Tb. of the oil in a large skillet and sauté the onions over low heat until caramelized about 25 minutes. Add the reserved marinade and cook another 6 minutes. Set aside.
3. Bake the mushrooms until softened about 30 minutes. Remove from the oven, cool and slice. Transfer to a plate and set aside.
4. Meanwhile, roast the peppers until charred all over, transfer to a bowl and cover with plastic wrap and cool. Split the peppers open, remove the seeds and membrane and chop. Transfer the peppers to a medium bowl and add the basil, garlic, another 2 Tb. of the oil and salt and pepper to taste.
5. Combine the arugula with 2 Tb. of olive oil, salt and pepper in a small bowl.
6. Arrange the bread on a baking sheet and brush lightly with olive oil. Toast for about 6 to 8 minutes.
7. Combine the aioli ingredients together in a small bowl.
8. Layer the toasts with slices of mushroom, arugula, onions and red pepper mixture. Season with salt and pepper. Serve with the rosemary aioli on top.