Can't wait for a repeat of this dish. Yum. Saute chopped onions with garlic. Brush baking dish with a little olive oil, and spread onions on the bottom. Layer summer squash, zucchini, potatoes, bell peppers and tomatoes. Sprinkle with sea salt and thyme. Cover with foil and bake at 325 for about 30 minutes. Uncover and sprinkle with shredded Parmesan cheese. Bake another 30 minutes or so.