Step 2

Remove the pan from the heat and quickly pour in the egg and cheese mixture. Using tongs or a long fork, lift the spaghetti to coat it evenly — the egg should thicken without scrambling.

Step 3

Finely chop the pancetta, removing any rind. Mix the Pecorino and Parmesan together in a bowl.

Step 4

Beat the egg yolks in a medium bowl and season with freshly ground black pepper. Set aside.

Step 5

Add 1 tsp salt to the boiling water, add the spaghetti and cook at a constant simmer, covered, for 10 minutes or until al dente.

Step 6

Squash the garlic cloves with the flat of a knife, just enough to bruise them. Melt the butter in a large frying pan or wok over medium heat and, as soon as it has melted, tip in the pancetta and garlic. Cook for about 5 minutes, stirring often, until the pancetta is golden and crisp at the edges. The garlic has done its job by now, so lift it out with a slotted spoon and discard it.

Step 7

Turn the heat under the pancetta down low. When the pasta is al dente, lift it straight from the water into the frying pan with tongs — a little pasta water coming with it is exactly what you want. Don't pour the pasta water away.

Step 8

Mix most of the cheese into the egg yolks, keeping a small handful back for serving.

Step 9

Add a few tablespoons of pasta cooking water to keep the sauce moist and glossy. Season with a little salt if needed.

Step 10

Twist the pasta onto warmed plates or into bowls. Sprinkle with the remaining cheese and a grating of black pepper. Serve immediately.