Put the sliced guanciale in a cold frying pan, then turn the heat to medium-low. Cook for 4-5 minutes, stirring occasionally until the fat has rendered and the guanciale is crisp and golden. Remove from the pan and set aside on kitchen paper to drain out the excess fat. Keep the fat in the pan and remove the pan from the heat.

Crack 2 eggs and 1 egg yolk into a large bowl, then add the pecorino/parmesan and a generous amount of cracked black pepper. Slowly pour the remnants of the oil from the pan into the cheesy egg mixture, whisking with a fork continuously as you pour so that the mixture is smooth. Don’t rush this - keep it moving so that the eggs don’t scramble.

Put the pan back over a low heat, then pour in the butter beans, and their bean stock, into the remaining guanciale fat. Fill the jar about ½ with water, give it a shake and pour about half in - this will act in a similar way to pasta water for that silky smooth finish. Increase the heat to medium and cook for 3-4 minutes until the beans are warmed through.

Remove from the heat and gradually pour in the cheesy egg mixture, mixing continuously. If it’s looking a little thick, pour in the remaining water from the jar to loosen the sauce. Add most of the guanciale to the pan and stir into the sauce, saving a few pieces for garnish.

Divide between bowls topped with more parmesan, the reserved guanciale and an extra few twists of cracked black pepper.