1Preheat the oven to 425°F. On a large rimmed baking sheet, toss together the onion slices, zucchini, squash, and bell pepper. Drizzle with olive oil and sprinkle with salt. Toss to coat evenly.
2Roast the vegetables until browned and tender, about 30 minutes, stirring once or twice during cooking. Transfer to a large, shallow serving bowl.
3While the vegetables are roasting, bring a large pot of salted water to a boil. Cook the pasta to al dente according to package directions.
4Add the pasta to the bowl along with the lemon zest and juice, olives, pine nuts, and Parmesan. Stir and toss to coat the pasta with the vegetables. Season with salt and pepper. Serve with the Parmesan sprinkled over the top.