PARSNIP SOUP

1/2 lb. parsnip, 1/4 lb. potato, 1/2 small onion, 1/4 oz. butter, pepper and salt, a little milk. Cut up the vegetables, cook them until tender, then rub through a sieve, return the mixture into a saucepan, add butter and seasoning, and as much milk as needed to make up the quantity of soup. Boil up and serve.