Preheat oven to 350 degrees F (175 degrees C). Coat bottom and sides of a 1 1/2 quart casserole dish with 1 tablespoon olive oil.
Heat remaining 1 tablespoon olive oil in a medium skillet over medium heat. Add chopped onion, garlic, parsley and chopped eggplant and cook while stirring until eggplant is soft, about 10 minutes. Season with salt to taste.
Spread eggplant mixture evenly across bottom of prepared casserole dish. Sprinkle with a few tablespoons of Parmesan cheese. Spread zucchini in an even layer over top. Lightly salt and sprinkle with a little more cheese. Continue layering in this fashion, with onion, mushrooms, bell pepper, and tomatoes, covering each layer with a sprinkling of salt and cheese.
Cover with foil and bake in preheated oven for 30 minutes. Remove foil and bake another 15 minutes to let the juice evaporate off.
