Boil a salted pot of water for the pasta and cook it al dente according to package directions.

When the pasta is about 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 1-2 minutes, stirring fairly often.

Add in the garlic, followed by the broth (or wine) and lemon juice + zest. Let it bubble for 1 minute.

Whisk in the cream 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 (I like to add a tablespoon or so of the pasta water to the sauce prior to draining it, especially if it's become a tad too thick). Garnish with more parmesan and a bit of chopped parsley if desired. Serve immediately.