Bring a large pot of water to a boil and salt it. Cook the fettuccine until it's al dente (check timing on the pasta bag or box and set a timer).
Cut the butter into 6 portions.
While the pasta cooks, add half of the butter in large chunks to a serving platter. Be sure the butter is not frozen, as you want the butter to be soft as it's waiting to be combined with the pasta and cheese.
Before straining the pasta, reserve 1 cup of the hot starchy pasta water. You could carefully ladle it out into a measuring cup.
Add ½ cup (about 3-5 tablespoons) of the hot pasta water to the platter with the butter and stir until the butter melts.
As soon as the pasta is al dente, strain the pasta and add it to the platter with the melted butter and pasta water and use tongs to combine it all together.
Add the other 3 portions of butter to the pasta and the other ½ cup of the hot pasta water. Use the tongs to combine it, stirring, until all the butter melts and the pasta is coated with the butter sauce.
Add the Parmigiano and use tongs to combine it all together with the butter sauce.
Serve immediately with some more freshly grated Parmigiano and a few cracks of some freshly ground black pepper (optional). Enjoy!
