2tablespoonsextra virgin olive oil,plus more for the eggplant
8ouncesbaby portobello mushrooms,sliced
8ouncesshredded mozzarella cheese
½cupfreshly grated Parmesan cheese
Coarse kosher salt and freshly ground black pepper
6whole wheat hoagie buns
Chopped fresh parsley(optional)
Heat the broiler to high and place a rack in the highest oven position.
Arrange eggplant in a single layer on a baking sheet and lightly brush both sides with olive oil. Broil 5-7 minutes per side or until soft and just beginning to brown. When the eggplant is done remove from the oven and move the oven rack to the middle position. Set the oven temperature to 400ºF.
In a large skillet, heat 1 tablespoon olive oil over medium heat. Add the onions and mushrooms and cook, stirring occasionally, until the mushrooms have released their moisture and the onions are soft, 5-7 minutes. Season with salt and pepper to taste.
In a medium bowl, combine breadcrumbs, Parmesan, and 1 tablespoon olive oil. Set aside.
Coat a 9x13 baking dish with cooking spray. Pour a little marinara sauce in the bottom of the pan and spread around evenly. Add the onion and mushroom mixture in an even layer, then top with the eggplant, slightly overlapping as necessary. Cover with the remaining marinara sauce. Sprinkle with mozzarella, then the breadcrumb mixture. Finally, sprinkle with salt and pepper to taste. Bake 20 minutes or until bubbly and beginning to brown.
In the last 5 minutes of baking, place opened hoagies on a baking sheet and toast in the oven until lightly browned. Serve scoops of eggplant bake in toasted buns and top with chopped parsley if desired.