Chestnut soup with Comté espuma

This exquisite soup is perfect for a special occasion, with the espuma adding a decadent finish. Make the soup a day ahead, leaving the espuma (which calls for a whipping siphon) and ceps to prepare before serving.

SERVES 6

20ml light olive oil

1 onion (100g), cut into large dice

50g celeriac (ideally) or celery, cut into large dice

500g vacuum-packed, cooked, peeled chestnuts, rinsed and drained

125ml dry Champagne or sparkling wine

1 litre chicken or vegetable stock

100ml milk

Sea salt and freshly ground pepper

For the Comté espuma

500ml whole milk

500ml double cream

100g Comté cheese (aged for 18–24 months), grated

A small pinch of cayenne pepper

For the garnish

2 firm, medium ceps

2 tbsp light olive oil

3 plump scallops, sliced in half horizontally (optional)

Heat the olive oil in a pan. Add the onion and celeriac or celery, and sweat over a low heat for 3–4 minutes, stirring occasionally. Add the chestnuts and two-thirds of the Champagne or wine and cook over a medium heat for 5 minutes. Add the stock and cook until the chestnuts collapse easily when pressed with a fork. Add the milk and some seasoning, and cook for another 2 minutes. Take off the heat.

Working in fairly small batches, blitz the soup in a blender for about 2 minutes until smooth, then strain through a fine chinois into a clean pan and set aside, covered to keep hot.

For the espuma, pour the milk and cream into a pan and slowly bring to the boil. Remove from the heat, add the grated Comté then blend to a creamy consistency. Season with salt, pepper and cayenne. Pour into the chamber of a whipping siphon, making sure it doesn’t come above the maximum level mark. Screw the top on to close the siphon, put the gas canister in the cartridge holder, then screw the base of it onto the siphon. This will puncture the canister and you will hear gas go into the chamber. Unscrew and remove the cartridge holder. Stand the siphon upright in a bain-marie at 50°C until needed.

For the garnish, using a small knife, pare the cep stalks and wipe the caps clean with damp kitchen paper, to remove all traces of grit and sand. Cut each cep into 6 slices. Heat the olive oil in a large frying pan, add the ceps and fry for 2 minutes on each side, until golden. Set aside on kitchen paper, sprinkling with salt and pepper to taste.

Cook the halved scallops, if using, in the same frying pan, without moving for 45 seconds, then turn them over and cook the other side for 30 seconds. Remove and set aside with the ceps.

Divide the remaining Champagne or wine between 6 shallow bowls, then pour in the hot chestnut soup. Top each serving with 2 cep slices and a scallop disc, if using. Take the siphon, turn it upside down and shake vigorously. Press the button and finish each soup with a generous rosette of Comté espuma. Serve at once.