Bring a large pot of salted water to a boil, add the bucatini and cook until just al dente (about 8 minutes).
Meanwhile, prepare the sauce. Warm olive oil in a large skillet over medium-low heat, then add the black pepper and cook until it just starts to sizzle (about 1 minutes). Take the skillet off the heat. Return the skillet over medium heat 1 minute before the pasta is done.
Drain the pasta well, reserving 1 cup of the starchy pasta water. Add bucatini to the skillet with the black pepper, and cook for 1 minute, tossing to coat in the oil. Reduce heat to medium-low, add 1/2 cup of the pasta cooking liquid, then gradually mix in the cheeses. Using tongs, stir and toss until the cheese melts and a sauce forms. Drizzle more starchy liquid in as you are stirring to thin out the sauce if needed. The bucatini should be evenly coated in the sauce, but you shouldn’t see liquid pooling in the bottom of the skillet. Season to taste with salt.
To serve, divide cacio e pepe between 2 plates and top extra Pecorino Romano and black pepper. Enjoy immediately.