Instructions

1. Trim the leeks, then cut them in half lengthwise and slice finely. Chop the garlic cloves.
2. Discard the outer skin of the lemon grass, then cut into thin slices with a sharp knife.
3. Peel the potato and cut it into cubes.
4. Heat the oil in a pan and gently fry the garlic and lemon grass until they soften (about 4-5 minutes).
5. Add the potato and the leek and sautée for about 7-8 minutes until they are tender.
6. Add the stock and bring to the boil. Simmer at low temperature for about 20 minutes.
7. Blend the soup until smooth and creamy (you can pass it through a sieve if you like it silky smooth).
8. Stir in the cream or yoghurt and serve with chopped chives or spring onions scattered on top.