Cook the Pasta:
Bring a large pot of salted water to a boil. Add pasta and cook according to package instructions until al dente. Reserve 1 cup of pasta water, then drain.
Make the Alfredo Sauce:
In a medium skillet or saucepan, melt the butter over medium heat. Add garlic and sauté for 1 minute until fragrant.
Pour in the heavy cream, stirring continuously. Bring to a gentle simmer, then reduce heat to low.
Add Cheese and Seasoning:
Gradually whisk in the Parmesan cheese, ensuring it melts smoothly into the sauce. Add salt and black pepper, tasting and adjusting as needed.
Combine Pasta and Sauce:
Add the cooked pasta to the skillet, tossing to coat evenly in the Alfredo sauce. If the sauce is too thick, add reserved pasta water a little at a time until the desired consistency is reached.
Serve:
Transfer the Pasta Alfredo to plates or a serving dish. Garnish with fresh parsley and additional Parmesan, if desired.