Melt the butter in a saucepan over medium-low heat.
Add the minced garlic and sauté gently for 30–60 seconds until fragrant, not browned.
Pour in the heavy cream and stir to combine.
Bring the mixture to a gentle simmer—do not let it boil.
Lower the heat and add the Parmesan cheese gradually, stirring constantly.
Continue stirring until the cheese melts fully and the sauce becomes smooth and creamy.
Season with salt and freshly ground black pepper to taste.
Remove from heat once the sauce coats the back of a spoon. Serve immediately.
Notes
Use freshly grated Parmesan; pre-shredded cheese can cause graininessKeep heat low at all times—Alfredo breaks easily if overheatedIf the sauce is too thick, add a splash of warm cream or pasta waterIf too thin, simmer gently for another minute or add a little more ParmesanBest served immediately, but can be reheated slowly over low heat with added cream