1 Heat the oil and butter and gently cook the leeks until soft but not brown.
2 Add the potatoes, stir for 2 minutes then add the stock. Bring to a boil then simmer for 25 minutes or until the potatoes are very tender.
3 Blend in the pan with a hand blender then add the cream, season with salt and pepper and reheat gently.
4 Serve garnished with the bacon and chives.