Heat the oven to 180C/fan 160C/gas 4. Spread the artichokes on a tray and drizzle over a little olive oil. Season with salt and pepper, and roast for 15-18 minutes until they’re golden brown and tender. In the meantime, add a drizzle of olive oil to a pan on a medium heat. Add the onion, garlic and thyme, season with salt and pepper, and fry for 10 minutes until soft but they don’t take on any colour.
Tip the cooked artichokes and half of the chestnuts into to the pan with the onions. Give everything a good stir and then add the chicken stock and simmer for 10 minutes. Add the cream and bring to the boil. Whizz in a liquidizer or with a stick blender until smooth and strain through a fine sieve.
Crush the remaining chestnuts into smaller pieces and dry fry until they become a little crunchy, take out and allow to cool a little.
To serve, heat the soup back up, pour into bowls, and sprinkle over the roasted chestnuts. Finish with a drizzle of olive oil and a few fresh thyme leaves.