I make the best onion soup the day after I have roasted a joint of beef on the bone and served it with roasted onions. I make the broth using the onion skins, cooking juices and beef bone, and then proceed as follows:
In a large heavy saucepan cook the onions very slowly in the butter to a soft translucency. It does not matter if they begin to turn golden; it is better that they do, since the sugar in the onions becomes more flavoursome as it caramelizes. However, they must not burn. And burnt onion skins should not be used, as they will add nothing but bitterness.
When the onions are soft, add the mace and red wine. Raise the heat, and let the wine almost evaporate. Stir in the beef broth, bring to the boil, season, and serve.
To dress it up, you can serve the soup French-style. Toast bread on one side, and then float a piece, toasted side down, on each bowl of soup, and heap with grated Gruyère or Comté cheese. Finish off under the grill or in the top of a hot oven. Sturdy, ovenproof soup bowls are essential in this recipe.
© 2000 Frances Bissell. All rights reserved.