Preheat oven to 350 Degrees. In a large mixing bowl combine sliced zucchini, onions, minced garlic, canned tomatoes, diced fresh tomato, spinach, Parmesan cheese, shredded basil leaves, salt and pepper. Stir to combine. Pour into casserole dish that has been sprayed with cooking spray. TOPPING: Combine bread crumbs, Parmesan cheese and olive oil. Sprinkle on top of casserole dish. Bake in preheated 350 degree oven for 30 minutes or until veggies are tender and top is browned. Remove from oven and allow to firm up for about 15 minutes, Top with shredded basil before serving.