The name of this classic Roman pasta dish translates as “cheese and pepper,” the cheese being pecorino and the pepper being black pepper. After dozens of rounds of testing, we developed an unusual technique of cooking the pasta in a 12-inch skillet with a minimal amount of water into which a small amount of all-purpose flour has been whisked. The starchy cooking water becomes the base for making a cheesy sauce that won’t break and has a silky and creamy, but not at all heavy, consistency. For this recipe, we found it best to avoid high-end spaghetti, the type with a rough, floury appearance, as the pasta tends to release a large amount of starch during cooking, making the sauce gluey and too thick. Widely available brands such as De Cecco and Barilla work nicely. It’s important to use true pecorino Romano cheese purchased in a chunk and to grate it finely with a wand-style grater or grind it finely in a food processor. Preground cheese lacks flavor and has a tendency to clump. Cacio e pepe is at its best hot, so we recommend serving in warmed bowls to slow the rate at which the pasta cools as it’s eaten.