Pre-heat oven to 350 degrees F. Lightly mist a shallow baking dish with vegetable oil cooking spray. Spoon marinara sauce onto the bottom of the prepared dish and set aside. Place two mushroom caps in the dish with the tops facing down.Place zucchini pieces in a microwave-safe container, add 1 teaspoon of water and microwave for 1 minute. Drain well and pat dry with paper towel.In a mixing bowl, combine the zucchini, ricotta cheese, egg, sundried tomatoes, pine nuts, Fontina cheese, 1/4 cup Parmigiano Reggiano and pepper. Spoon an even amount of this mixture into each mushroom cap. In a small bowl, combine the remaining 1/4 cup Parmigiano Reggiano and bread crumbs. Divide and sprinkle this mixture over each filled mushroom cap. Spray caps generously with vegetable oil cooking spray and bake for 15 to17 minutes. Increase heat to broil and broil for 1 to 2 minutes, or until the bread crumbs are golden.
