Add the spaghetti and cook until al dente according to the package instructions. Reserve about 1½ cups of pasta water before the pasta is finished cooking. Do not drain the pasta.

In the final 2 minutes of pasta cooking, place a nonstick skillet over medium heat. Add the black pepper and toast it for 30 seconds to 1 minute, stirring frequently, until fragrant. Be careful not to let it burn.

Add the olive oil and about ½ cup of the reserved pasta water to the skillet. Stir to combine, letting the flavors blend.

Using tongs, transfer the cooked spaghetti directly into the skillet. Stir well to coat the noodles in the peppery oil mixture. Cook for about 2 minutes, stirring constantly, to let more starch release from the pasta.

Remove the skillet from heat and let it cool for 30 seconds. This step helps prevent the cheese from clumping or separating.

Working in small batches, sprinkle in the finely grated Pecorino Romano cheese while stirring continuously. Stir gently but constantly until the cheese melts and forms a creamy sauce. If the sauce is too thick or clumpy, gradually add more reserved pasta water, ¼ cup at a time, until it reaches your desired consistency.

Taste and adjust with kosher salt if needed. Serve immediately, topped with more Pecorino Romano cheese and a pinch of freshly ground black pepper.