Drain and rinse the soaked chestnuts, removing any loose skins or damaged nuts.
Fry chestnuts, vegetables, spices, and fat in a 1.5 litre saucepan until browned.
Add 570ml water and 570ml wine, bring to a boil, and simmer covered for 90 minutes.
Strain the stock into a clean pan and reserve the chestnuts for garnish.
Discard the boiled vegetable mixture.
Mix yeast extract, cornflour, and tomato purée with 4 tbsp cold water to form a paste.
Stir the paste into the hot stock and simmer for 5 minutes until thickened.
Serve the gravy and chestnuts with a nut roast.