Step 1

In a large heatproof bowl, combine butter and cheese. In a medium pot of salted boiling water, cook pasta until al dente. Using tongs, a strainer, or a spider, transfer pasta to bowl with cheese and butter.

Step 2

Add 1/2 cup hot pasta-cooking water, then, using tongs, toss repeatedly until butter is melted and a creamy, emulsified sauce forms. If pasta seems too dry, add a splash or two of additional pasta water until desired consistency is reached. Season with salt, if necessary. Serve, sprinkling more cheese on top at the table.