1. Add the oil and the butter to a large pan and turn the heat to medium. Add in the leeks, celery and onion along with the thyme leaves and the peeled garlic. Season with salt and pepper and place a lid on and allow the vegetables to sweat for 10 minutes, stirring a few times in between.
2. Now add the chopped parsnips and the chestnuts along with the stock, bring to the boil and simmer until the parsnips are tender. Make sure the vegetable are completely covered with stock, if not, add a little more as it depends on the size of your pan.
3. After about 20 minutes all the vegetables should be nice and tender.
4. Turn off the heat and blend either in a liquidiser or with a handheld blender. Never over fill your liquidiser, so do this in batches and I would recommend leaving the soup to cool slightly before doing this.
5. Blend until completely smooth before returning to the pan and reheating. You can add a little more stock if you feel the mix is too thick.
6. Season with a little more pepper before serving with a few more chopped chestnuts and a few fresh thyme leaves.
Chef’s tip: dress soup with a drizzle of oil for a tasty finishing touch.
Our thanks to www.Britishleeks.co.uk for permission to use this recipe.