Set up your pots and pans. Bring a large pot of well-salted water to a boil. Place a large skillet over medium heat for the bacon. Have a heatproof mixing bowl ready for the egg mixture, plus tongs for tossing.

Mix the sauce base. In the bowl, whisk together the eggs, extra yolk, and grated Pecorino until thick and smooth. Add a generous amount of black pepper. Do not add salt here; the cheese and bacon will handle that.

Crisp the bacon. Add chopped bacon to the skillet (a touch of olive oil if needed). Cook over medium heat until the fat renders and the edges are crisp, 6–8 minutes. Turn off the heat. Do not drain all the fat; you want 1–2 tablespoons in the pan for flavor.

Cook the pasta. Drop the spaghetti into boiling water and cook until just shy of al dente. Start checking a minute earlier than the package suggests. Before draining, reserve at least 1 cup of the starchy pasta water.

Marry pasta and bacon. Transfer the drained pasta directly into the skillet with the bacon and rendered fat. Toss over low heat for 30 seconds, coating the strands and letting the pasta cool slightly. This step helps prevent scrambling later.

Temper the eggs. Add a small splash (about 1/4 cup) of hot pasta water to the egg-cheese mixture while whisking constantly. This warms the eggs gently so they’re ready to form a sauce.

Create the sauce off the heat. Turn the skillet heat off. Pour the tempered egg mixture over the pasta and quickly toss with tongs, lifting and folding until glossy. Add more hot pasta water, a few tablespoons at a time, until the sauce turns silky and clings to the noodles. It should look creamy, not runny.

Season and finish. Taste and add more pepper as needed. If it tastes too salty, loosen with a bit more pasta water and add a small handful of Parmesan to balance sharpness. If it’s too thick, another splash of water will smooth it out.

Serve immediately. Plate it hot, with extra grated cheese and a final grind of black pepper. Add a sprinkle of chopped parsley if you like a fresh note.