1 bunch broccoli, cut into 1-inch pieces (about 4 cups)
10 ounces short pasta, such as fusilli
5 teaspoons extra-virgin olive oil
1/2 ounce Parmesan, finely grated (1/4 cup), plus more for serving (optional)
1 teaspoon finely grated lemon zest, plus 1 tablespoon lemon juice
1/2 cup packed fresh parsley leaves
1/2 small garlic clove
1 can (15 1/2 ounces) cannellini beans, rinsed and drained
In a large pot of boiling salted water, cook broccoli until tender and bright green, about 4 minutes. With a slotted spoon, transfer broccoli to a food processor. Return water to a boil and cook pasta according to package instructions. Reserve 2 cups pasta water; drain pasta and return to pot.
To food processor, add oil, Parmesan, lemon zest and juice, parsley, and garlic. Puree until smooth, about 2 minutes, scraping down side as needed. Transfer pesto to pot with pasta. Stir to coat, adding enough reserved pasta water to make a creamy sauce. Stir in beans and heat over medium until warmed through. Season with salt and pepper. To serve, sprinkle with Parmesan, if desired.