Put the onion, white part of the leek
and carrots in a large pan and pour on
a few tbsp of the stock. Cook over a
medium heat for about 10 mins, stirring
regularly until soft. Add a splash more
stock if the vegetables start to stick.
Add the potato, green leek and most
of the stock, and simmer for 10-15 mins,
until the potato is tender. Tip in the
sweetcorn and crab meat, then cook
for a further 1-2 mins. Remove from the
heat and stir in the crème fraîche and
some seasoning. Add the rest of the
stock if the soup is too thick. Sprinkle
with the chives and serve with brown
bread, if you like.