01 - Bring a large pot of generously salted water to a rolling boil. Add the mafaldine and cook according to package directions. During the last 5 minutes of cooking, add the broccoli florets to the pot. Cook until the pasta is al dente and the broccoli is tender-crisp. Reserve ⅓ cup of starchy pasta water before draining through a colander.
02 - While the pasta cooks, warm the olive oil in a large skillet over medium heat. Add the minced garlic and sauté for about 1 minute, stirring frequently, until fragrant and just softened — avoid letting it brown.
03 - Pour the heavy cream into the skillet and bring to a gentle simmer. Stir in the lemon zest, lemon juice, and Parmesan cheese. Season with salt and freshly ground black pepper. Continue stirring until the cheese has melted and the sauce is smooth.
04 - Add the drained pasta and broccoli to the skillet. Toss everything together thoroughly, splashing in the reserved pasta water a little at a time until the sauce reaches a silky, coating consistency. Taste and adjust seasoning as needed.
05 - Divide among warmed plates or bowls. Finish with torn fresh basil leaves, an extra shower of Parmesan, and a light grating of lemon zest if desired. Serve immediately while hot.