Gather your ingredients: Before you start cooking, make sure you have everything ready: guanciale, finely chopped tomatoes, bucatini pasta, chili flakes, Pecorino Romano cheese, white wine, and salt.
Cook the pasta: Bring a large pot of salted water to a boil. Cook the bucatini until al dente, following the package instructions. Reserve about ½ cup of pasta water before draining.
Cook the guanciale: Place the sliced guanciale in a large skillet over medium heat. Let it slowly render its fat and turn golden and crispy, about 5–7 minutes. If the guanciale is very lean, you can add a small splash of olive oil to help it cook evenly. Once crispy, use a slotted spoon to remove the guanciale and set it aside, leaving the rendered fat in the pan.
Deglaze with white wine: Add a splash of white wine to the pan. Let it simmer for 30–60 seconds, stirring gently, until the alcohol reduces and the flavorful bits loosen from the bottom of the pan.
Add tomatoes and chili flakes: Stir in the finely chopped tomatoes and chili flakes. Simmer gently for about 5 minutes, allowing the sauce to thicken and soak up the guanciale flavor. When the sauce has thickened enough, return the sautéed guanciale to the pan and stir well.
Toss the pasta and finish: Turn off the heat. Add the drained bucatini to the skillet with the sauce. Sprinkle in the finely shredded Pecorino Romano cheese. Toss everything together, adding a little reserved pasta water as needed to help coat the noodles evenly.
Taste and adjust: Taste the pasta and adjust if needed — add a little extra Pecorino Romano, a sprinkle of black pepper, or a touch more pasta water for the perfect creamy texture.