Add the fettuccine and cook according to the package instructions until al dente.
Reserve about 1 cup of pasta cooking water before draining.
Melt the Butter:
In a large skillet or pan, melt the butter over medium heat.
Add Pasta and Cheese:
Once the butter is melted, add the cooked fettuccine to the pan.
Reduce the heat to low and gradually add the grated Parmesan cheese, tossing the pasta continuously to coat it evenly with butter and cheese.
Create the Sauce:
Slowly add some of the reserved pasta water, a little at a time, tossing the pasta until a smooth, creamy sauce forms. The starchy pasta water helps to emulsify the butter and cheese, creating a creamy texture.
Continue to add pasta water as needed until you reach your desired sauce consistency.
Season And Serve
Season with salt and freshly ground black pepper to taste.
Serve the fettuccine Alfredo immediately, garnished with extra Parmesan if desired.