Bring a large pot of water to a rolling boil and salt it generously. This is your only chance to season the pasta itself!
While the water heats, place your softened butter in a large, warm serving bowl. Having the bowl warm prevents the butter from seizing when the hot pasta is added.
Cook the pasta according to package directions until al dente (tender but with a slight bite).
Before draining, carefully reserve about 1 cup (240 ml) of the starchy cooking water. This is liquid gold!
Drain the pasta and immediately add it to the bowl with the softened butter.
Toss vigorously to melt the butter and coat the pasta.
Add a splash of the reserved pasta water to help create a smooth, emulsified sauce.
Add the grated Parmesan cheese and a generous amount of black pepper.
Continue to toss, adding more pasta water a tablespoon at a time as needed, until the cheese melts and the sauce is creamy and glossy.
Serve immediately, passing extra cheese at the table.
Don't be shy with cheese variations! Swap Parmesan for a vegetarian Pecorino Romano for a sharper bite, or add a dollop of mascarpone for extra creaminess.
