Leek, onion and potato soup

An Irish recipe for the week that’s in it!  (St Patrick’s day March 17)image
4 large leeks
2 medium potatoes, peeled and diced
1 medium onion, chopped
50g butter
850 ml chicken stock /water
275 ml milk
Salt and pepper
To serve :1 ½ tablespoons chopped chives
2 tablespoons crème fraîche (optional)

Trim off the tops and roots of the leeks, discarding the tough outer layer. Slice them up finely and rinse thoroughly.In a large pot, melt the butter and add the leeks, potatoes and onion stirring them with a wooden spoon. Season with salt and pepper, cover and let the vegetables sweat over a very low heat for about 15 mins.Then add the stock and milk, bring to a simmerinig point, replace the lid and simmer very gently for 20 mins. Liquidise to a purée. Reheat very gently. Add the chives and the cream just before serving.