Heat oil in a large heavy-based pan. Add celery, carrots and thyme, then gently fry for 15 mins.
Stir in stock, bring to a boil, cover, then simmer for 10 mins.
Add the chicken, remove half the mixture, then purée with a stick blender.
Tip back into the pan with the rest of the soup, chives and seasoning, then simmer for 5 mins until hot through, then serve.
Recipe from Good Food magazine
1 tbsp olive oil
2 sticks celery, chopped
3 medium carrots, chopped
1 tbsp thyme leaves, roughly chopped
1 tbsp chopped chives
1.4l chicken stock
300g leftover roast chicken, shredded and skin removed