Preheat the oven to 450ºF.On a rimmed baking sheet, toss the broccoli with the olive oil, cayenne, garlic powder, and a big pinch each of salt and black pepper. Roast for 15 to 20 minutes, tossing once, until lightly charred.Meanwhile, bring a large pot of salted water to a boil over high heat. Add the pasta and cook until al dente according to the package directions. Reserve 1 cup of the pasta cooking water, then drain the pasta and immediately return it to the pot. Add the hummus, about ½ cup of the pasta cooking water, the lemon zest, lemon juice, butter, and Parmesan. Toss until a creamy sauce forms. Thin the sauce with more pasta cooking water, a little at a time, as needed. Add the basil, parsley, and red pepper flakes. Taste and season as needed with salt and black pepper.Add the broccoli to the pasta and toss gently. Serve immediately with extra Parmesan and fresh basil and/or parsley on top.