This section is from the book "The Epicurean", by Charles Ranhofer. Also available from Amazon: The Epicurean, a Complete Treatise of Analytical and Practical Studies on the Culinary Art.
Cut into small eighth of an inch squares, two medium or four ounces of onions, fry them in butter and moisten with two quarts of broth, adding a bunch of parsley garnished with chervil, bay leaf and a clove of garlic; season with a little salt, pepper and some meat extract; boil for twenty minutes, then remove the bouquet, and pour the soup over very thin slices of bread placed in a metal soup tureen, in intervening layers of bread and cheese, parmesan, finishing with the parmesan, and sprinkle a little over the top of the soup. Bake in a hot oven.
To prepare onion soup cut up two medium onions, mince them finely, and fry them colorless in butter, adding two dessertspoonfuls of flour, and cooking it a lew moments with the onions, then dilute with two quarts of broth. Season with pepper and a little salt, boil for ten minutes, and just when ready to serve thicken the soup with raw egg-yolks diluted in cream, and a little flue butter. Pour the soup over round, thin slices of bread, about one inch and a quarter in diameter, dried in the oven.
 
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