Pumpkin and Chestnut Soup, from the Aveyron

• 300 g fresh chestnuts peeled (see below) or use vacuum packed chestnuts
• 3 tbsp olive oil

To peel the chest nuts make a cut on the flat side with a sharp knife. Drop them into salted boiling water and boil for 10 minutes. Fish them out one at a time and peel off inner and outer skin while still hot. If this is all too fiddly, use some vacuumpacked chestnuts ready to go.

Heat the oil in a large saucepan and soften the onion, celery, lemon peel and sage leaves, sprinkled light