Prep your ingredients: Finely grate the cheese, dice the pancetta, and separate the eggs. In a bowl, whisk the egg yolks and whole egg with most of the cheese and a hearty pinch of black pepper. Reserve a little cheese for serving.

Boil the pasta: Bring a large pot of well-salted water to a boil. Cook spaghetti until just shy of al dente. Before draining, reserve 1–1½ cups of hot starchy pasta water.

Crisp the pancetta: While the pasta cooks, place pancetta in a large, cool skillet and set over medium heat. Let the fat render and the meat turn golden and crisp, 6–8 minutes. If using garlic, add it for the last minute to perfume the fat, then remove and discard.

Control the heat: Turn the skillet heat to low. You want it warm, not sizzling, to avoid scrambling the eggs.

Combine pasta and pancetta: Add drained spaghetti directly to the skillet with the pancetta and rendered fat. Toss to coat so every strand gets a sheen.

Temper the egg mixture: Whisk about 2 tablespoons of hot pasta water into the egg-cheese mixture to loosen it. This step reduces the risk of curdling.

Create the sauce: Remove the skillet from the heat. Pour the tempered egg mixture over the pasta, tossing quickly and continuously. Add hot pasta water a splash at a time until the sauce turns silky and clings to the noodles. You may use ½–1 cup total. Work off the heat to prevent scrambling.

Adjust and season: Taste and add more black pepper or a tiny pinch of salt if needed. Fold in the remaining cheese for extra body.

Serve immediately: Plate the pasta while it’s glossy and hot. Top with a final shower of cheese and more pepper.