Boil the squash, onion, bell pepper, and celery in salted water until tender and drain the liquid. Mix the tomatoes, egg, cheese, bread crumbs with the vegetables and transfer to a baking dish. Bake at 350 degrees for 30-45 minutes or until slightly browned on top. *You can substitute 2/3 cup of bread crumbs for the toasted bread. I used Italian flavored bread crumbs.