Place the carcass, chopped vegetables, bouquet garni with 2 litres of water in a large saucepan. Bring to the boil, then reduce to a simmer and cook for 1.5 hours, skimming when needed. Pass through a sieve. Discard carcass.
Yield of pure flavourful stock will be 1 litre.
Add cream and 200g chestnuts to the stock and bring to a boil, add salt to taste then blitz with butter for 3-4 minutes. Strain and pour it in the soup bowl.
Roughly cut the bread into an inch dice, place it on a baking tray, drizzle with olive oil, lightly season with salt and crushed black pepper, and bake in 170°C pre-heated oven for 5-7 minutes, turning once in between. It should turn golden brown and crisp. Take out and let it cool down naturally.
Garnish with remaining crumbled roasted /sous vide chestnuts, baked bread croutons, drizzle of truffle oil and few truffle shavings.