Bring a large pot of lightly salted water to a boil. Add penne pasta, cook for 10 to 12 minutes, until al dente, and drain. Lightly grease a medium casserole dish.
Preheat the oven to 350 degrees F (175 degrees C). In a blender or food processor, thoroughly mix Parmesan cheese and crackers.
Heat oil in a skillet over medium heat. Place onion in the skillet, and cook and stir until tender. Mix in zucchini, tomato, and garlic, and season with oregano, basil, celery, salt, and pepper. Continue to cook and stir until zucchini is tender.
In the prepared casserole dish, mix pasta with vegetable mixture and mozzarella cheese. Top evenly with Parmesan cheese mixture.
Bake 25 minutes in the preheated oven, or until the topping is lightly browned. Allow it to stand 5 minutes before serving.
Zucchini Pasta Bake · Dinner Match Lab | Dinner Match Lab