Wash and trim the leeks then cut into rings. Finely chop onions. Peel and dice potato

In deep pan cook onion and leeks in the butter until softened. Add potatoes and vegetable stock. Bring to boil then reduce heat and simmer for 20 minutes

Add milk then blend until smooth

Transfer the soup to a bowl and whisk in the cream yoghurt salt and pepper.

Leave to cool then chill for an hour if you are having it cold. You can warm it up before serving

Garnish with chopped cilantro