The key to bucatini all'amatriciana is guanciale: cured pork jowls, akin to pancetta or unsmoked bacon, cooked until crispy, then sauced with San Marzano tomatoes. It's classic Roman cuisine—just a few choice ingredients, deftly combined, in all of 30 minutes from start to finish.
Sauce, part 1: Dice the guanciale, then sauté in olive oil over medium heat, 6–8 minutes or until the guanciale is crisp.
Pasta: Meanwhile, bring a large pot of salted water to a boil. Add pasta to the boiling water and cook until al dente, about 3 minutes less than what the box advises. (Chef Mantuano advises using bronze-cut pasta for his dishes. These noodles are made with bronze molds instead of Teflon, for a surface texture that's a bit rougher and more porous. This greatly helps the sauce to cling to each noodle.)
Sauce, part 2: Add the tomatoes to the crispy guanciale and bring to a simmer. Using a wooden spoon, stir the sauce occasionally, breaking up the tomatoes as they are cooking, 5 minutes. Set aside.
Assembly: Reserve ½ cup of the pasta water, then drain the bucatini. Return the pasta to the pot. Season the sauce with chili flakes and black pepper. Pour sauce and reserved pasta water into the pot and cook over low heat, tossing the pasta with the sauce to allow them to "marry," 2 minutes. The pasta should still be firm to the bite.
Transfer the pasta to a platter. Grate Pecorino Romano directly on top, about ½ cup. Serve immediately, passing more cheese at the table.