Pierce the chestnuts and roast at 180°C/ gas mark 4, for 10 minutes. Cool, then peel the chestnuts, set aside.
Sweat the chopped onion, garlic, celery and leeks in 1 tbsp of olive oil for 5 minutes.
Add ¾ of the chopped mushrooms fry for 5 more minutes. Optional: in a separate pan fry the remaining ¼ of the mushrooms to use as a topping.
Add in the stock and chestnuts, then simmer for 20 minutes.
Blend into a soup with a tablespoon of Greek yoghurt.
In a dry pan, toast the pecans for 2 minutes. Add in maple syrup and coat until caramelised.
Pour the soup into bowls and place a teaspoon of yogurt in the middle, swirl it outwards. Sprinkle over the pecans and parsley to garnish.
Season with salt and pepper to taste.
As an option, add your mushroom topping.