01 - Preheat the oven to 400°F.
02 - In a large mixing bowl, combine sliced zucchinis, cubed eggplant, chopped bell peppers, sliced red onion, and halved cherry tomatoes with 1 tablespoon olive oil, salt, and black pepper. Toss to coat evenly.
03 - Spread the vegetable mixture evenly into a 9x13 inch baking dish.
04 - In a separate bowl, blend crushed tomatoes, minced garlic, remaining 1 tablespoon olive oil, dried oregano, dried basil, chili flakes (if using), salt, and pepper until well mixed.
05 - Pour the tomato sauce evenly over the arranged vegetables and gently mix to coat all pieces.
06 - Cover the baking dish with aluminum foil and bake for 30 minutes.
07 - Remove the foil, sprinkle with grated Parmesan if using, and bake uncovered for an additional 15 minutes until vegetables are tender and the top is lightly golden.
08 - Garnish with chopped fresh parsley before serving.