This is my absolute favourite soup. Watercress has such a beautiful, rich flavour and this is a fabulously healthy recipe.
Around 6 servings, freezes well
2 medium potatoes (approx 300g)
1.2 litres vegetable stock
300g watercress (thick stalks removed), washed, plus extra for garnishing
salt and freshly ground black pepper
Cut the leeks in half horizontally then slice, discarding the dark green part. Wash and drain.
Peel the potatoes then chop into small chunks.
Heat the oil in a heavy-based pan and add the leeks and potatoes. Stir well to coat then cover and cook over a gentle heat for 15 minutes, stirring occasionally.
Add the stock and the watercress and bring to the boil. Reduce to a simmer and cook, uncovered, for a further 15 minutes until the vegetables are tender.
Allow to cool a little then liquidize in batches or blend until smooth with a stick blender. Return to the saucepan and season to taste. Reheat then serve in hot soup bowls. Garnish with some watercress leaves and a drizzle of olive oil.