Bring a large pot of water to a rolling boil, add a generous pinch of salt, and cook the spaghetti until al dente according to package instructions. Drain and set aside, reserving about 1 cup of pasta water.
Heat a large skillet over medium heat, add the diced pancetta or guanciale and olive oil. Cook, stirring occasionally, until the meat is crispy and golden brown, about 5-7 minutes. Remove from heat and set aside.
400 g spaghetti
In a mixing bowl, whisk together the eggs, grated Pecorino Romano cheese, and a generous amount of freshly ground black pepper until thoroughly combined.
400 g spaghetti
Add the cooked spaghetti to the skillet with pancetta, tossing to coat the pasta in the rendered fat. Remove from heat to prevent the eggs from scrambling.
400 g spaghetti
Slowly pour the egg and cheese mixture into the hot pasta, tossing vigorously with tongs or a fork to create a creamy sauce. If necessary, add reserved pasta water a tablespoon at a time to achieve desired looseness and silkiness of the sauce.
400 g spaghetti
Serve immediately, garnished with extra black pepper and additional grated Pecorino Romano if desired, ensuring the pasta remains warm and creamy.
400 g spaghetti
