How to Make It
Bring a large pot of generously salted water to a boil. Add your pasta.
When the pasta is a few minutes from al dente, place the black pepper in a dry skillet and gently toast over medium-low heat, swirling the pan to keep the spice moving (to keep it from burning). Toast the pepper until it’s fragrant and warm, about 1 minute.
Add the butter to the skillet. Increase the heat to medium and, gently swirling the pan over the heat, cook until the butter is melted.
At this point, your pasta should be ready to drain, but before you drain it, reserve 3/4 cup of pasta cooking water. (If you need a minute or two to continue cooking your pasta at this point, remove your butter mixture from the heat but be sure to warm it up again for a minute or so before you continue with the next step.)
Add 1/2 cup pasta cooking water to the butter mixture, along with your drained pasta, and another tablespoon of cold cubed butter to the skillet. Reduce the heat to medium-low/low and add 3/4 cup of finely grated Parmigiano or Grana Padano cheese, stirring constantly with tongs until the cheese is melted. Remove the pan from the heat and add 1/3 cup of finely grated Pecorino Romano cheese, stirring and tossing until the cheese is melted and the sauce is creamy. Add more pasta cooking water if the sauce seems dry.
Transfer the pasta to warm bowls and serve immediately, topping with more cheese and freshly ground black pepper, if desired.