Get a medium sized saucepan. Add the vegetable oil, onion and garlic. Put a lid on. Sweat over a medium heat for 7-8 minutes until soft but not starting to go brown.
Take the pan off the heat. Add the brandy. Put the pan back on the heat, boil until there is almost no liquid left to remove the alcohol, be very careful if you are cooking on gas as the brandy will catch alight.
Add the vegetable stock and chestnuts. Bring to the boil. Reduce by half. Take the pan off the heat.
Cool slightly. Transfer to a blender. Add the walnut oil. Blend until the mixture is totally smooth.
Toss the vegetables with the salt, sugar and vinegar. Leave to sit for 5 minutes. You will have a lot of these, any leftover will keep for a few days.
Serve the chestnut ‘foie gras’ with the quick pickled vegetables and grilled or toasted bread.
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