Strip all the meat from the chicken carcass, shredding it into bite-sized pieces. Transfer to a plate along with any skin you can salvage and any jellied juices and fat, then chill until needed. Put the carcass in a large saucepan with the carrot, halved onion and bay leaves. Cover with cold water, then bring to the boil. Reduce the heat to a gentle simmer, cover and cook for at least 30 mins and up to 2 hrs until you have about 1 litre of stock. Strain through a sieve into a large jug or pan. Discard the bones, bay and veg. If you end up with more than 1 litre of stock, continue to cook over a high heat to reduce. Whisk in the stock cubes until dissolved, then keep the pan warm over a low heat while you make the risotto.

Heat a large casserole or high- sided frying pan over a low heat. Melt the butter, add the oil and fry the chopped onion for 10 mins until soft and translucent. Add the garlic and stir for 1 min more, then add the rice. Cook, continuing to stir for a few minutes until the rice has absorbed some of the butter and is shiny. Pour in the wine and stir until the liquid has bubbled away.

Add the lemon zest and thyme, then a generous ladleful of the warm stock. Continue to cook the risotto over a low-medium heat for 20 mins, stirring often, adding the stock a ladleful at a time and allowing it to be absorbed before the next addition. Add the reserved chicken and any jellied juices and fat towards the end of the cooking time to warm through. The risotto should be loose and soupy, and the rice grains very nearly cooked, but still retaining a little bite. Stir in some more stock to loosen if needed (or kettle-hot water if you’ve run out), then a large knob of butter and the parmesan. Season well and cover. Leave for a few minutes for the butter and cheese to be absorbed while you make the crackling.

Tear or chop the chicken skin into small pieces, then put in a cold, dry frying pan. If the skin is quite lean (with no fatty patches) add a drizzle of oil; otherwise, the fat should render from the skin and start to sizzle. Fry for a few minutes until the skin is crisp, then transfer to a plate lined with kitchen paper.

Check the consistency of the risotto again – the rice will absorb more stock as it rests, so you may need to add more. Spoon into bowls, drizzle with truffle or olive oil, and top with some shaved parmesan and the chicken crackling.