START TO FINISH: 35 minutes
SERVINGS: 4
Romans use the leaves that grow around heads of broccoli to make a flavorful sauce for pasta. In the U.S., most of the leaves are stripped off before broccoli is sold. Our recipe instead uses the stems, which are equally flavorful and produce a silky sauce. Baby spinach maintains the color of the original recipe.
Don’t undercook the broccoli stems. We’re accustomed to cooking vegetables until crisp-tender, but the stems here should be cooked until fully tender.
Kosher salt and ground black pepper
1 pound broccoli, stems and florets separated
1½ cups packed baby spinach
2 medium garlic cloves, chopped
4 tablespoons (½ stick) salted butter, cut into 4 pieces
1 tablespoon drained capers
½ teaspoon red pepper flakes
2 tablespoons grated lemon zest, divided
12 ounces rigatoni pasta
1 ounce pecorino Romano or Parmesan cheese, finely grated (½ cup), plus more to serve
In a large pot, bring 4 quarts water and 2 tablespoons salt to a boil. Peel the broccoli stems, reserving any leaves, and cut crosswise into ½-inch rounds. Add the stems and leaves to the boiling water and cook until fully tender, about 10 minutes. Stir in the spinach and cook until wilted, about 20 seconds. Using a slotted spoon, transfer the vegetables to a blender; reserve ½ cup of the cooking water. Keep the water at a boil.
Cut the broccoli florets into 1- to 1½-inch pieces. Add the florets to the boiling water and cook until crisp-tender, about 3 minutes. Using the slotted spoon, transfer to a colander and rinse under cold water until cooled. Again, keep the water at a boil.
To the blender, add the garlic, butter, capers, pepper flakes, ¾ teaspoon salt, 1 tablespoon of the lemon zest and the reserved broccoli cooking water. Puree until smooth and bright green, about 30 seconds. Taste and season with salt and pepper.
Stir the rigatoni into the boiling water and cook until al dente. Reserve ½ cup of the cooking water, then drain. Return the pasta to the pot and add the broccoli florets, the broccoli puree, ¼ cup of the reserved cooking water, the remaining 1 tablespoon lemon zest and the cheese.
Cook over medium, stirring constantly, until the sauce thickens slightly and the pasta is well coated, 1 to 2 minutes. Remove from the heat. Taste and season with salt and pepper.