Spaghetti With Roasted Vegetables, Pine Nuts, and Olives

Ingredients (12)

• 12 ounces spaghetti
• 1 small red onion, peeled, halved and sliced
• 2 zucchini (about 3/4 pound), trimmed, quartered lengthwise, and cut into 1/2-inch chunks
• 2 yellow squash (about 1/2 pound), trimmed, quartered lengthwise, and cut into 1/2-inch chunks
• 1 red bell pepper, seeded, sliced, and cut into 1/2-inch pieces
• Olive oil
• Kosher salt and freshly ground black pepper
• Zest and juice of 1 lemon
• 1/2 cup chopped, pitted black olives such as kalamata
• 1/3 cup toasted pine nuts
• 1/2 cup freshly grated Parmesan, plus more for serving
• Chopped fresh flat-leaf parsley leaves for garnish