All of this should be done at the same time. You want the bacon grease to be hot at the same time the pasta is finished cooking.

Bring a large pot of lightly salted water to a boil. Add the pasta and cook until just done or al dente. This is one of the few times where you don't want to heavily salt the water. There is plenty of salt in the bacon and cheese.

Meanwhile, slowly cook the bacon or Pancetta in a large pan over low heat. Make sure the fat from the pork is fully rendered (if not, the sauce will not come together properly). Remove the pan from the heat when done. If your bacon is particularly fatty, you can remove part of it. But you will want about 3-4 tablespoons of the flavorful fat.

In a separate bowl, beat the egg and yolks until combined. Add the grated cheese and a generous amount of freshly ground black pepper.

When the pasta is done, drain (reserving one cup of the cooking water).

Add the cooked spaghetti to the pan with the cooked and rendered bacon, including the rendered fat.

Stir the pasta and bacon until every noodle is coated with fat.

Quickly, but slowly pour in the egg and cheese mixture, stirring and tossing continually.

Start to pour in a bit of the starchy pasta cooking water, stirring constantly. Add the water slowly, but keep in mind that it's best to add more liquid than necessary—the pasta will absorb more as it sits. Continue to add a dribble of water until you get a nice velvety sauce.

Let the pasta sit for a minute, covered.

Serve with extra cheese on top if desired.