Cut four large onions in large pieces and put them in six ounces of
butter with pepper and salt. Slowly stew this in a little beef stock and
a little milk, stirring constantly, for one hour. Add more stock and
milk and let cook slowly for another hour. In a tureen place slices of
bread sprinkled with two tablespoonfuls of Parmesan cheese. Beat the
yolks of four eggs and mix them with a tablespoonful of the soup and
pour this over the bread and cheese. Cover this for five minutes and
then pour over it the rest of the soup.