Boil a salted pot of water for the pasta and cook it al dente according to package directions.
When the pasta is approx. 10 minutes away from being done, add the butter to a skillet over medium-high heat. Once it melts, sprinkle the flour in and cook for about a minute, stirring fairly often.
Add in the garlic, followed by the broth (or wine) and lemon juice + zest. Let it bubble for one minute.
Whisk in the cream, then stir in the chicken, and cook it for a few minutes until the sauce has thickened up to your liking.
Stir in the parmesan cheese and take the skillet off the heat. Season with salt & pepper as needed (I am generous with both).
Add the drained pasta to the skillet and toss until coated (add a tablespoon or so of the pasta water to the sauce prior to draining it, especially if the sauce has become a little too thick). Serve immediately with more parmesan and a bit of chopped parsley if desired.
I do NOT recommend subbing the heavy cream for anything with a lower fat content (e.g. half-and-half or milk) because the lemon in the sauce is very likely to curdle it, and you'll have to add more flour to thicken the sauce.
Nutritional information is provided as a courtesy only and should be construed as an estimate rather than a guarantee. Ingredients can vary and Salt & Lavender makes no guarantees to the accuracy of this information.