Marinated Portobello Mushroom Sandwiches

Scrape out and discard the gills of each mushroom. Cut caps into ½-inch thick slices. In a small bowl, mix together the oil (5 Tbsp), vinegar, oregano and fennel, reserving 2 tablespoons. Place the sliced portobellos in the marinade for 20 minutes. Mix together the onion and remaining marinade in a small bowl and set aside. Place tomatoes, garlic, parsley, basil, pine nuts, olive oil (2 Tbsp) and Parmesan in a food processor and blend until the mixture is a spreadable paste, adding water as needed. Season to taste with pepper and set aside. Heat a large skillet over medium-high heat. Remove the mushrooms from the marinade and sauté for 5-10 minutes until just tender. Remove from heat. Season with salt and pepper. To assemble sandwiches, place provolone slices on the bottom half of each ciabatta roll, then divide the sun-dried tomato spread, sautéed mushrooms, marinated onions and lettuce evenly among the four sandwiches. Top with the other half of the roll and serve.