Another Carrot and Coriander Soup

oil or butter
1 medium onion, sliced
9 cups/700g/l ? lbs carrots, sliced
1 tsp/5ml ground coriander
3 ? cups/900ml/ ? pts vegetable stock
2/3 cup/150ml/ ? pt soured cream
salt and freshly ground black pepper
parsley to garnish
serves 6-8
Heat the oil, add the onion and cook until it has just softened but not browned. Add the carrots and coriander and stir well. Leave the carrots to cook gently for 3 minutes.
Pour in the stock and bring the mixture to the boil, then simmer, covered, for 25 minutes.
Liquidize the soup, adding the soured cream. Adjust the seasoning. Serve very cold, garnished with parsley.