Cook the pasta in salted water until al dente. Reserve a cup of the starchy cooking water, then drain. Don’t rinse—the starch is your friend.
In a large skillet, melt butter over medium heat. Add minced garlic and sauté 30–60 seconds until fragrant—but not brown. We’re aiming for perfume, not a garlic clown show.
Pour in the heavy cream. Simmer gently for 2–3 minutes, stirring. It should thicken a bit, not scorch your optimism.
Stir in grated Parmesan until melted and silky. If it’s stubborn, splash a little pasta water to loosen.
Fold in the cooked chicken. Let it warm through, about 2 minutes. Season with salt, pepper, and optional nutmeg or lemon juice.
Toss the pasta into the sauce, or spoon sauce over pasta in the pan. Add a splash more pasta water if you want a looser, creamier coat.
Garnish with parsley if you’re feeling fancy. Serve hot and devour.