Meanwhile in a saute pan, heat the extra-virgin olive oil. Add the garlic, and pancetta, and cook for a few minutes. Remove the garlic when it is golden brown, and then lower the heat.
In a bowl, whisk together the milk, pecorino cheese, salt, and lots of black pepper. Separate the eggs, making sure not to break the yolks. Add the egg whites to the milk mixture, and mix well.
When the spaghetti is at the 'al dente' stage, drain well. Add the pasta to the saucepan with the pancetta, and remove from heat. Pour in the milk mixture, and stir for a minute or so. The heat from the spaghetti will cook the egg and thicken the sauce.
Plate and garnish each serving with an egg yolk* on top. Add the fresh ground black pepper and serve immediately.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.