01 - Bring a large pot of generously salted water to a rolling boil. Add the mafaldine and cook according to package directions, subtracting 2 minutes from the recommended time so the pasta is slightly underdone.
02 - Three minutes before the pasta finishes cooking, add the broccoli florets directly into the boiling pasta water. Scoop out 1/2 cup of the starchy cooking water and set aside, then drain the pasta and broccoli together in a colander.
03 - While the pasta cooks, heat the olive oil in a large skillet over medium heat. Add the sliced garlic and chili flakes, stirring gently for 1 to 2 minutes until fragrant and just softened, making sure the garlic does not brown.
04 - Transfer the drained mafaldine and broccoli into the skillet with the aromatics. Pour in the lemon juice and scatter the zest over the top, adding a splash of the reserved pasta water. Toss vigorously, drizzling in more cooking water as needed until a silky, glossy sauce coats every strand.
05 - Sprinkle the grated Parmesan over the pasta and toss continuously until the cheese melts and the sauce thickens, clinging to the noodles. Season with salt and freshly ground black pepper to taste.
06 - Divide the pasta among warm plates or shallow bowls. Finish with an extra shower of Parmesan and a scattering of fresh basil or parsley. Serve right away while hot.