Lettuce and Potato Soup

Put a pan over medium-heat and melt the butter. Add the sliced onions and fry it for 3 minutes. Add the sliced potatoes, stir gently and cook it for 5 minutes. Add the chicken stock, pepper and salt to taste. Cover the pan and simmer it for at least 10 minutes. Leave to cool. With the help of a blender make it to a smooth puree. Add the milk and light cream, and mix properly. Your lettuce and potato soup is ready to serve.