Cook pasta in well-salted water, until about 2 minutes before al dente. Drain, reserving 1 cup pasta water.

Just before pasta is finished, melt 2 Tbsp. butter in a large skillet over medium heat. Once butter is melted, add pepper and cook about 1 minute while swirling the pan.

Add 1/2 cup reserved pasta water to skillet and bring to a simmer. Add pasta and remaining butter. Reduce heat to low and add Parmesan, tossing until melted. Add salt to taste. Remove from heat and add Pecorino, stirring and tossing until cheese melts and sauce coats the pasta. Add more pasta water if necessary.

Serve and top with additional Parmesan as desired.