How to Make It
Cook broccoli in a large pot of salted water until very tender, about 12 minutes. Using a slotted spoon, transfer to a bowl, shaking off excess water. Set aside.
Return water in pot to a boil. Add pasta and cook according to package directions. Drain, reserving 1 cup cooking water in a small bowl. Return drained pasta to pot.
Blend reserved 1 cup cooking water, broccoli, Parmesan, oil, garlic, 1 teaspoon salt, and black pepper in a blender until smooth, stopping to scrape down sides of bowl as needed.
Add broccoli mixture to pasta in pot and toss to coat. Serve pasta topped with ricotta and crushed red pepper, if using.