The best pasta carbonara

Ingredients:

• 4 large eggs + 2 yolks
• 1 cup freshly grated Parmesan cheese, plus extra for serving
• 0.5 tbsp. freshly grated pecorino romano
• 1 tbsp freshly ground black pepper
• 2 tablespoons unsalted butter, room temperature (optional)
• 450 g spaghetti
• 1 piece of pancetta (340 g), cut into strips

Preparation:

1. Bring salted water to a boil in a saucepan over high heat.
2. In a large bowl, combine the eggs, yolks, Parmesan, pecorino, pepper, and butter, if using. Add the pasta and cook according to package directions. Set aside 1 cup of water, and drain the rest in the sink.
3. Meanwhile, in a large skillet over medium heat, cook the pancetta, stirring occasionally, until crisp, about 8 minutes. Add the spaghetti and half the cooking water and stir.
4. Add the egg mixture and stir to coat the pasta. Cook, stirring constantly to prevent the eggs from curdling, until the sauce is smooth, thinning it with reserved pasta water if necessary (the sauce should be pourable but not watery), about 1 minute.
5. Divide the pasta among plates and sprinkle with additional Parmesan.