Le Thourin is another soup from southwestern France, this time from Périgord. One white version is creamy and thick, based only on onion and milk spiked with garlic; another more closely resembles Gratinée Lyonnaise. The common denominator seems to be onion and garlic, here combined with tomato for a lively first course. It is quick to prepare but must stand an hour or two so the flavor develops. Need I say that fresh ripe tomatoes are essential?
Melt the fat in a soup pot over low heat. Add the onions and garlic, season with salt and black pepper, and press a piece of aluminum foil down on the vegetables. Cover the pan and sweat the vegetables over very low heat, stirring occasionally, until soft, 15 to 20 minutes. Do not let them brown.
Stir in the flour, add the tomatoes, and leave to cook, uncovered, for 2 minutes. Stir in the water and bouquet garni, season with salt and pepper, and simmer gently, uncovered, until reduced by about one-third, 25 to 30 minutes. When the simmering is done, the broth should be well flavored but not too concentrated. Let the soup stand for an hour or two off the heat, so the flavor develops before serving, then discard the bouquet garni. The soup is even better stored in the refrigerator overnight.
To finish, make the croûtes. Bring the soup to a boil, and simmer for 5 minutes. Put 2 to 3 croûtes in each soup bowl. Add the cayenne pepper to the soup, taste, and adjust the seasoning. Spoon into the bowls and serve very hot.
© 2007 All rights reserved. Published by Chronicle Books.