How to Make It
Preheat oven to 425°F. Toss together butternut squash, 1 tablespoon oil, and ½ teaspoon salt on a large rimmed baking sheet. Roast until tender and lightly browned, about 20 minutes, stirring once halfway through cook time. Remove from oven.
While squash roasts, prepare pasta according to package directions; do not drain. Transfer pasta to a large bowl using a slotted spoon, reserving cooking water in pot. Cover pasta to keep warm.
Return cooking water in pot to a boil over high; add broccoli, and cook, undisturbed, until tender, about 5 minutes. Transfer broccoli to a cutting board using a slotted spoon, reserving cooking water in pot. Let cool 5 minutes. Coarsely chop 2 cups of the broccoli, and add to pasta in bowl.
Place remaining broccoli in a food processor; add packed basil leaves, Parmesan cheese, 2 teaspoons lemon zest, 2 tablespoons lemon juice, garlic, ½ cup of the cooking water, and remaining ¼ cup oil and ¼ teaspoon salt. Process until smooth, about 15 seconds, adding additional cooking water as needed to achieve desired sauce consistency.
Add broccoli sauce to pasta and broccoli in bowl; toss to coat. Serve topped with roasted squash and sprinkled with crushed red pepper, if desired. Garnish with sliced basil and more lemon zest.