Preheat oven to 350F. Wash, cut and halve eggplants and zucchini and one bell pepper. Using a spoon hollow out eggplants and zucchini to create a boat;transfer them to baking dish. Roughly chop scooped-out eggplant and zucchini flesh,mushrooms,one bell pepper.In a large skillet over medium heat, heat oil. Add onion and cook until soft, 5 minutes. Stir in chopped eggplant and zucchini and season w salt and pepper

Meanwhile sprinkle oil and bake boats about 20 mints,then (layer baking dish with tomato sauce) transfer the boats back to tomato sauce layered dish,add tomato sauce,then scoop the mixture into eggplant boats.add mozzarella cheese evenly to the boats.,

If you have left over tomato sauce pour over the boats.bake about 40-45 mints,add Parmesan and use broil setting if you want until the color of cheese change.