How to Make It
In a large, deep skillet, heat the oil. Add the onion and cook over moderately low heat until very soft, 7 minutes. Add the guanciale and cook until translucent, 3 minutes. Add the vinegar, wine, tomatoes and 2 tablespoons of water and simmer until thick, 30 minutes. Season with salt and pepper.
In a pot of salted boiling water, cook the bucatini until al dente; reserve 2 tablespoons of the cooking water. Drain the pasta, add it to the sauce along with the reserved cooking water and cook over moderate heat, stirring, for 1 minute. Remove the skillet from the heat and stir in 3 tablespoons of cheese. Serve right away, passing more cheese at the table.
Guanciale is available at Italian markets or online at salumeriarosi.com.