STEP 1 Put a large saucepan of water on to boil.
STEP 2 Dice 100g Guanciale , having first removed any rind. Finely grate 100g pecorino cheese
STEP 3 Beat the 3 large eggs with grated cheese in a medium bowl and season with a little freshly grated black pepper. Set everything aside.
STEP 4 Add 1 tsp salt to the boiling water, add 350 g spaghetti and when the water comes back to the boil, cook at a constant simmer, covered, until al dente (just cooked).
STEP 5 While the spaghetti is cooking, fry the guanciale with little olive oil.
STEP 6 Leave to cook on a medium heat for about 5 minutes, stirring often, until the guanciale is golden and crisp.
STEP 7 Keep the heat under the guancialeon low. When the pasta is ready, lift it from the water with a pasta fork or tongs and put it in the frying pan with the pancetta. Don’t worry if a little water drops in the pan as well (you want this to happen) and don’t throw the pasta water away yet.
STEP 8 Take the pan of spaghetti off the heat. Now quickly pour in the eggs and cheese. Using the tongs or a long fork, lift up the spaghetti so it mixes easily with the egg mixture, which thickens but doesn’t scramble, and everything is coated.
STEP 9 Add extra pasta cooking water to keep it saucy (several tablespoons should do it). You don’t want it wet, just moist. Season with a little salt, if needed.
STEP 10 Use a long-pronged fork to twist the pasta on to the serving plate or bowl. Serve immediately with a little sprinkling of the remaining cheese and a grating of black pepper. If the dish does get a little dry before serving, splash in some more hot pasta water and the glossy sauciness will be revived.