How to make leek and potato soup

An autumn favourite of mine, leek and potato soup. The recipe is:

• chop 5 medium sized leeks, 4 medium potatoes and a large onion and add to a pan with a bit of oil. Cook gently for about 10 minutes.
• add a litre of stock and a couple of cloves of crushed garlic, bring to the boil and simmer for about 15 minutes.
• add half a litre of milk and simmer for a further 10-15 minutes.