Cacio e Pepe

• 8 oz spaghetti or tonnarelli
• 1 1/2 tsp whole black peppercorns, coarsely cracked
• 1 1/2 cups (3 oz) very finely grated Pecorino Romano, plus more to serve
• 1 tbsp butter (optional, for insurance)
• Kosher salt, for the pasta water

1. 1Bring a wide pot with just 2 quarts of water to a boil and salt it lightly (Pecorino is salty). Less water means starchier water, the key to the sauce.
2. 2Toast the cracked pepper in a large dry skillet over medium heat until fragrant, about 1 minute. Add 1/2 cup of pasta water and let it simmer.
3. 3Cook the pasta until 2 minutes short of al dente. Transfer it to the skillet with tongs and toss over medium heat, adding splashes of pasta water, until just al dente.
4. 4In a bowl, mash the Pecorino with 1/3 cup lukewarm (not boiling) pasta water into a smooth paste.
5. 5Take the skillet off the heat and let it cool for 30 seconds. Add the butter and cheese paste and toss vigorously, adding pasta water a spoonful at a time, until the sauce is creamy and clings to the noodles.
6. 6Serve immediately with more Pecorino and pepper.

Tap a step to mark it done.