Bring a large pot of salted water to a rolling boil. Add the pasta and cook according to package directions until al dente. Reserve about 1 cup of the pasta water before draining.

While the pasta is cooking, melt the butter in a large skillet over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant, being careful not to burn it.

Pour in the heavy cream and bring to a gentle simmer. Cook for 2-3 minutes, stirring occasionally, until the cream has slightly thickened.

Reduce the heat to low. Gradually whisk in the grated Parmesan cheese until the sauce is smooth and creamy. Stir in the chopped parsley and red pepper flakes, if using.

Season the sauce with salt and freshly ground black pepper to taste. Remember that Parmesan cheese is salty, so adjust accordingly.

Add the drained pasta directly to the skillet with the sauce. Toss well to coat every strand. If the sauce seems too thick, add a splash of the reserved pasta water, a tablespoon at a time, until it reaches your desired consistency.

Serve immediately, garnished with extra Parmesan cheese and fresh parsley.