Serves 4

200g/7oz dried porcini mushrooms
600ml/1pint warm water
150ml/1/4pint extra-virgin olive oil
1 banana shallot, peeled and finely chopped
20 small Roseval potatoes
4 sprigs of rosemary, leaves, finely chopped
3 cloves of garlic, peeled and finely chopped
10 chestnuts, peeled
100g/31/2oz Parmesan, grated
Sea salt and ground black pepper
Put the dried porcini in the warm water and leave to soak for 20 minutes. Place a pan over a low heat, add a tablespoon of the oil and the shallots; cook over a gentle heat for 10 minutes or until translucent.

While the shallots are cooking, slice the potatoes thinly. Then add the rosemary, garlic and potatoes, turn the heat to low and cook for five minutes. Add the rest of the olive oil – it may seem a lot but it is what makes the soup taste so rich. Stir well to combine and cook for 10 minutes.

Next roast the chestnuts (see recipe on page 67). Add along with the porcini and the water they were soaked in. Turn up the heat and cook until the potatoes are tender, stirring from time to time. Finish with the Parmesan, black pepper and a pinch of salt. Serve nicely warm.