Bring a large pot of salted water to a boil over medium high heat.
Add the pasta to the pot and stir. Cook until al dente, approximately 7-8 minutes.
Drain the pasta reserving 1 cup of the pasta water
Return the pasta back to the pot or a skillet and place over low heat.
Add the butter to the pasta and pour the reserved water over it to melt. Toss the pasta to combine.
Stir in the cheese and pepper continuing to toast until the cheese becomes a creamy sauce.
Top with more cheese and serve immediately.
Notes
Cacio e pepe is best served soon after making.Pecorino is traditional but you can substitute with parmesan or other hard cheese for variations on flavor.