Toast the peppercorns in a small frying pan over a gentle heat for 1–2 minutes until fragrant, then grind or crush them to a rough powder using a pestle and mortar.
In a bowl, whisk together the egg yolks and whole egg 2–3 minutes until pale and creamy. Add the pecorino and mix together well, until glossy and thick. Sprinkle over the nutmeg and a little of the crushed pepper.
Fry the pancetta in a small frying pan over a medium heat in a little olive oil, stirring, for 10 minutes until lightly golden. Spoon off and discard half the fat from the pan and set the pancetta and remaining fat aside.
Bring a large saucepan of salted water to a boil, add the spaghetti /tagliatelle and cook according to the packet instructions; or if fresh, just 3-4 minutes until al dente. Drain the pasta, reserving a cupful of the cooking water, and return to the pan.
Reheat the pancetta pan, add 2 tablespoons of pasta water, add the pancetta back in and warm through. Add the tagliatelle, followed by the cheesy egg mixture. Mix through, remove from the heat and keep working the sauce through the tagliatelle to coat well. Serve with a sprinkle of grated pecorino or Parmesan.
