1tbsp olive oil
1 medium onion, chopped
500g potatoes, peeled and diced
500g trimmed leeks, sliced
1litre vegetables stock OR 500ml milk and 500ml water
chopped parsley for garnish
Warm oil in a large saucepan over moderate heat. Add onion. Cover and cook for 5min.
Add potatoes and leeks. Stir well and cook for 10min.
Pour in liquid and bring to the boil for 5min, stirring, then simmer until vegetables are tender. Allow to cool slightly.
Liquidize in blender or food processor. Return to pot and stir in cream and seasonings. Reheat gently and garnish with parsley.