This is a dish I seldom order in a restaurant because there's a better than even chance they'll ruin it by adding cream. Authentic carbonara does not have any cream in it. In fact, it was conceived as a dish to eat when one has been out late (or early, as the case may be) and is looking for a little something to snack on.
1/2 lb dried spaghetti
4 oz pancetta, but into small dice
1 tbs extra virgin olive oil
2 large eggs, at room temperature
2 oz finely grated Pecorino-Romano cheese
freshly ground black pepper
Optional garnish: braised leeks
Bring an 8 quart pot of water to a rapid boil. Add the pasta and 2 tbs salt and cook until al dente. Reserve 1 cup of the pasta water, then drain.
While the pasta is cooking, put the pancetta and oil in a large heavy duty skillet and cook over medium heat, stirring occasionally. Cook until golden brown (5-7 minutes), but don't render all the fat. Remove the skillet from the heat.
In a medium bowl, whisk the eggs and cheese along with 1/4 tsp freshly ground black pepper. Slowly whisk in about 1/4 cup of the reserved pasta water.
Immediately after draining the pasta, add it to the skillet, then quickly pour in the egg mixture, tossing continuously with tongs until the pasta is well coated (15-30 seconds). Add more of the reserved water if needed to achieve a creamy consistency. Serve immediately with more freshly ground black pepper to taste.
This is a dish best eaten as soon as it is prepared. Frankly, leftovers do not reheat well, so plan to eat it all up or eat the leftovers cold. Don't let the simplicity fool you. Carbonara is a very satisfying dish, unfussy, but unctuous.