1. Place a large pot of cold, salted water on the stove.
2. Heat the olive oil in a frying pan and add the guanciale. Fry on a very low heat until the fat melts and the guanciale is slightly crispy.
3. When the water is boiling put the spaghetti in the pot. The cooking time of spaghetti is indicated on package.
4. Lightly beat the eggs with a pinch of salt in a bowl.
5. When the spaghetti is done, drain it well. Put the beaten egg, cooked guanciale (including the melted fat), and spaghetti into pasta pot. Mix them as soon as possible.
6. Transfer the food to dish plate.
7. Add cheese and black pepper, serve at once.
Guanciale is Italian cured pork jaw meat. If guanciale is not available it can be substituted with pancetta (Italian cured pork belly). If neither is available American bacon may be used, in this case remember to throw away about half the melted fat in step 5.
In step 5, make sure to mix all the ingredients and serve very quickly, otherwise the egg will be too dry and sticky.