Slice six parboiled onions and fry lightly in an ounce of butter with a little parsley and pepper and salt. Add them to a quart of white stock - chicken broth or fish stock is preferable - with one and a half tablespoonfuls of flour, and then stir in a pint of hot milk. Press the whole through a cloth or sieve and serve as hot as possible. Small slices of toast should be served with the soup.