Creamy Lemon Chicken Pasta with Spinach

Bring about 4 l (4 qt) water to a boil in a large pot and add the salt. Cook the pasta 1 minute less than the package directions, stirring in the first minute. Before draining, scoop out a mug of the starchy cooking water (you need about 180 ml), then drain.

While the water heats, pat the chicken dry and season with 3/4 tsp kosher salt and pepper. Heat the oil in a 12-inch (30 cm) skillet over medium-high heat. Add the chicken in a single layer and cook without stirring 3 minutes until golden underneath, then turn and cook 2–3 minutes more until cooked through to 165°F (74°C) — check the largest piece. Transfer to a plate.

Lower the heat to medium, add the butter to the same skillet and, once it foams, add the garlic and pepper flakes; cook 45 seconds until fragrant. Pour in the cream and the lemon zest, scraping up the browned bits, and simmer gently 2–3 minutes until slightly thickened.

Add the drained pasta and 120 ml of the pasta water to the skillet and toss over medium-low heat for 1–2 minutes until the pasta is al dente and the sauce clings. Take off the heat, add the Parmesan in handfuls, tossing to melt, then add the spinach and chicken and toss until the spinach just wilts. Stir in 2 tbsp lemon juice, taste, and add more lemon, salt, pepper or a splash of pasta water to loosen. Serve immediately.