Celeriac is a beautiful winter vegetable gradually finding favour worldwide. This soufflé is also excellent if made with pumpkin instead of celeriac; it then becomes a classic French dish.
100g/¼lbceleriac, peeled and chopped
4tablespoonsdry white wine
1teaspoonkuzu flour or arrowroot dissolved in water
50g/2oz/½cupsweet chestnuts, chopped
50g/2oz/½cupGruyère, Cheddar or hard cheese, grated
Simmer the celeriac in the wine, butter, seasoning and celery salt for 20 minutes. Mash coarsely. Heat the kuzo with the milk to make a sauce. Stir in the chestnuts, cheese and egg yolks. Pre-heat the oven to 220°C/425°F/Gas mark 7. Whip the whites stiffly and fold in gradually. Bake in a buttered 1.5-litre/2½-pint/l½-quart soufflé dish for 20 minutes.