There are almost endless possibilities for variation here. Potatoes are my favorite thickening agent for garlic soup, but it can also be thickened with a roux of flour and butter or with bread, the traditional choice in the South of France, where this dish is a specialty. Onions and scallions can be used instead of leeks, although the soup won’t have the same subtle taste. If you use the leeks, include most of the green leaves.
Poultry or meat stock gives the soup more body and flavor, although it’s good made with water. I have purposely kept the soup simple, but for a party, you could enrich it by adding a cup of light cream at the last minute.
Excerpted from Essential Pépin, © 2011 by Jacques Pépin. Reproduced by permission of Houghton Mifflin Harcourt. All rights reserved.
Harold McGee, the author of Keys to Good Cooking, is an expert on the chemistry behind food and cooking. McGee recently made his first trip to China, where he learned more about rice wine.