Salt the pasta water: Bring a large pot of water to a boil and salt it generously. You want it to taste like the sea.

Cut the chicken: Slice chicken into thin strips or small bite-size pieces. Pat dry and season well with salt and pepper.

Cook the pasta: Add pasta to the boiling water. Cook until just shy of al dente, usually 1 minute less than package directions. Reserve 1 cup of pasta water, then drain.

Blanch the broccoli: During the last 2 minutes of pasta cooking, add broccoli florets to the pot. Drain with the pasta. The broccoli should be bright green and crisp-tender.

Sear the chicken: Heat olive oil in a large skillet over medium-high. Add chicken in a single layer and cook without moving until golden on one side, 2 to 3 minutes. Flip and cook another 2 to 3 minutes, until cooked through. Transfer to a plate.

Sauté the garlic: Reduce heat to medium. Add butter to the skillet. When melted, add garlic and a pinch of red pepper flakes. Cook 30 to 60 seconds until fragrant, not browned.

Build the sauce base: Pour in chicken broth and simmer 2 minutes, scraping up browned bits. For a thicker sauce, sprinkle in flour and whisk for 30 seconds.

Add cream and Parmesan: Stir in heavy cream and bring to a gentle simmer. Add Parmesan a handful at a time, stirring until smooth. Season with salt, pepper, and lemon zest. Taste and adjust. A little lemon juice brightens the sauce—start with 1 teaspoon.

Toss it all together: Add cooked chicken, pasta, and broccoli to the skillet. Toss to coat. If the sauce is too thick, loosen with reserved pasta water, a splash at a time, until glossy and silky.

Finish and serve: Turn off heat. Taste and adjust lemon, salt, and pepper. Garnish with chopped parsley or basil and extra Parmesan. Serve warm.