In a skillet, cook the bacon pieces over medium low heat until the fat is rendered out, so the bacon pieces are golden but not darkened & crisp - about 4-5 minutes.
Meanwhile, bring a pot of water to a boil and season generously with kosher salt (about 1 tablespoon for about 2.5 quarts of water).
In a large bowl, add 3 egg yolks, 1 full egg, and ½ teaspoon fresh ground black pepper. Whisk to combine and set aside.
Add the pasta to the boiling salted water and cook according to package instructions/your desired doneness. Save about ½ cup of pasta water before draining.
When the bacon is done, use a slotted spoon to remove the bacon pieces from the pan, letting excess fat drip back into the pan, and transfer to the bowl with the egg mixture. Add 1 teaspoon rendered bacon fat from the pan to the egg mixture.
When the pasta is done, immediately add the hot pasta to the egg & bacon mixture and stir well with tongs to coat. Sprinkle on about half the cheese and 1 tablespoon pasta water and continue tossing until the cheese is well distributed. Add the remainder of the cheese and continue to toss to thicken. The sauce should be velvety, glossy and cling to the noodles. If it seems too dry, add a little more pasta water. Divide among serving bowls and garnish with a little more cheese and fresh ground pepper.
Notes
Carbonara is traditionally made with guanciale (Italian cured pork jowl) but it is hard to find. Pancetta is a good substitute but can also be hard to find in standard supermarkets, so this recipe substitutes easy-to-find bacon. If you have access to guanciale or pancetta, feel free to substitute!You can use all Parmigiano Reggiano, all Pecorino Romano, or any combination of the two cheeses that you prefer - the total amount of cheese should be about 1 oz (about ¼ cup tightly packed). Parmigiano Reggiano is a little nuttier and sweeter, and Pecorino Romano is a little sharper and tangier. I really like the combo of half and half! I noted both the weight and the approximate volume of the cheese because the amount of shredded cheese in ¼ cup changes drastically based on how finely it's grated and how tightly it's packed. Adapted from Bon Appétit's The Silkiest Carbonara