This is an adaptation from my grandmother's (nonna's) recipe. I lightened it up by reducing the egg (originally 4) to 2 eggs and the equivalent of 2 extra egg whites. If cooked properly and the temperature of the pasta is maintained, it is the creamiest and most divine pasta dish one can expect. —EatPrayandEatAgain
In a heavy bottom large pan add the olive oil and the pancetta together with the whole garlic clove to brown. When the pancetta is crispy but not yet browned turn off the fire and set aside.
Meanwhile cook the spaghetti in plenty of salted water till al dente (this is one of the secrets here, as the pasta will continue to cook with the sauce I usually drain up to two minues short of the recommended cooking time for real al dente)
In a bowl whisk the eggs and egg whites until blended. Add salt and pepper (careful as thepancetta is already salty is better to adjust the salt at the end).
When pasta is cooked drain. Reheat the olive oil with the pancetta until very hot and pour the cooked spaghetti. Mix well to coat the pasta and incorporate the flavors.
Add the two types of grated cheeses and continue to mix. Adjust salt and pepper and serve immediately in pre-heated bowls decorated with chopped prsley and grated pepper.