Preheat the oven to 375°F (190°C).
Cook ziti pasta according to package instructions until al dente.
Heat olive oil in a large skillet over medium heat. Add the onion and sauté until translucent.
Add minced garlic, bell pepper, spinach, mushrooms, and zucchini. Cook until vegetables are tender.
Stir in crushed tomatoes, oregano, basil, salt, and pepper. Simmer for 5 minutes.
Combine the cooked ziti with the vegetable sauce mixture in a large bowl.
Transfer the mixture to a greased baking dish. Top with mozzarella and Parmesan cheese.
Bake in the preheated oven for 25–30 minutes, until the cheese is bubbly and golden.
Let cool for 5–10 minutes before serving.