Ingredients

• 5 oz guanciale (unsmoked cured hog jowl) or pancetta
• 1 medium onion, finely chopped
• 1/4 cup dry white wine
• 1 lb spaghetti
• 3 large eggs
• 1 1/2 oz Parmigiano-Reggiano, finely grated (3/4 cup)
• 3/4 oz Pecorino Romano, finely grated (1/3 cup)
• 1 teaspoon coarsely ground black pepper
• 1/4 teaspoon salt

Instructions

1. Cut guanciale or pancetta into 1/3-inch dice, then cook in a deep 12-inch heavy skillet over moderate heat, stirring, until fat begins to render, 1 to 2 minutes. Add onion and cook, stirring occasionally, until onion is golden, about 10 minutes. Add wine and boil until reduced by half, 1 to 2 minutes.
2. Cook spaghetti in a 6- to 8-quart pot of boiling salted water until al dente.
3. While pasta is cooking, whisk together eggs, Parmigiano-Reggiano , Pecorino Romano (1/3 cup), 1 teaspoon coarsely ground black pepper, and 1/4 teaspoon salt in a small bowl.
4. Drain spaghetti in a colander and add to onion mixture, then toss with tongs over moderate heat until coated. Remove from heat and add egg mixture, tossing to combine. Serve immediately.