A little technique transforms simple ingredients into an extraordinary pasta dish. The famed Roman pasta dish cacio e pepe (“cheese and pepper” in Italian) is, at its heart, a showcase for Pecorino Romano, a sharp, nutty, pleasantly funky sheep's-milk cheese from the region. For a top-notch version for two, we started by cooking 8 ounces of spaghetti in 1½ quarts of boiling water until it was al dente. Using the right amount of cooking water was important because we reserved some of it to stir back into the pasta later. The correct measurement ensured that the water had just the right starch content to produce a creamy, silky sauce. Once the pasta was finished cooking, we reserved ½ cup of the cooking water, drained the pasta, and returned it to the pot. Grating 2½ ounces of Pecorino Romano cheese on a rasp-style grater ensured that it dissolved more readily. Reserved cooking water and 2 tablespoons of butter stirred in with the cheese helped create the sauce. After thoroughly tossing the pasta with tongs, we covered it and allowed it to sit for a minute so that the residual heat could fully melt the cheese and butter and the pasta could drink up all the excess liquid. We added a generous amount of freshly ground black pepper and tossed the pasta again to break up any clumps of cheese that may have formed and to thoroughly coat every noodle with the creamy sauce. The pepper wasn't a gimmick here; its clean, spicy flavor cut through the richness of the butter and cheese, earning its place in the dish's name. An extra sprinkle of grated cheese gave the pasta another layer of salty richness, and a drizzle of bright extra-virgin olive oil added sheen and reinforced the peppery punch.