- Heat the oil in a large pan and add the onions, potatoes and leeks. Cook for 3-4 minutes until starting to soften.
- Add the vegetable stock and bring to the boil. Season well and simmer until the vegetables are tender.
- Whizz with a hand blender or in a blender until smooth. Reheat in a clean pan, stir in the cream or crème fraîche, heat through and serve.