Add the pancetta to a large sauté pan or frying pan with the olive oil. Place on a medium heat and cook for about 5 minutes over a medium heat to render out the fat, then add the chopped onions

Keep on a medium heat and slowly cook the onions with the pancetta until golden brown, about 10–15 minutes, stirring often. It is important to do this slowly as you want the onions to become slightly sweet and caramelised but not to burn. If they start to stick to the pan add a couple of tablespoons of water and continue to stir

Add the chopped sage and cook for a further 2 minutes, then set aside

Season the livers with salt and pepper. Add the vegetable oil to a large, heavy based frying pan and place on a high heat. When the oil is very hot (almost smoking) add the livers to the pan in one layer and sauté for 1–2 minutes on each side. You may have to do this in batches so as to not overcrowd the pan – if there are too many in a pan the heat will drop and the livers will begin to boil rather than fry. You want the livers slightly pink in the middle

Once cooked, remove the livers from the pan and leave to cool on a tray or large plate

Return the pan to a medium heat and add the marsala to deglaze and gently scrape the pan with a spatula to lift off all the flavour left behind by the livers. After one minute, add the marsala to the cooked onions and pancetta

When the livers are cool enough to handle, roughly chop them up and add them to the onions and pancetta and stir together well

Bring a large pan of water to the boil and season well with salt

Cook the pasta as per the packet instructions

Halfway through the cooking time, return the pan with the livers to the stove along with the butter and a ladle of the pasta cooking water. Heat through gently to melt in the butter until you have a saucy consistency

Drain the pasta, reserving some of the water, and add to the sauce

Toss together vigorously until the sauce thickens and coats the pasta well. If it is too thick add a little of the pasta cooking water, if it is too thin keep tossing over the heat

Check the seasoning and serve immediately, topped with freshly grated Parmesan