When made with the best ingredients, this soup is redolent of mushrooms, the pepper is aromatic but not biting, and the soup has a brothlike consistency, rather than gelatinous from too much cornstarch. Traditionally, this soup is made with pork and pork broth, but any meat and any broth will work. In fact, it is particularly good with duck. For the best results, look for dried shiitake mushrooms with caps that have a network of fissures revealing white flesh. Depending on their size—and size seems to have little effect on flavor—these mushrooms will run anywhere from expensive to very expensive. Fortunately, a few go a long way, and it is worth buying a lot because they will keep for years. Some of the ingredients in this soup—the tree ears, tiger lily stems, and tofu—are morefor texture than flavor and can be left out. I call specifically for Japanese tofu because I prefer its texture. If you are using raw meat, make sure it is from a tender cut, as tough cuts won’t have time to tenderize. Use the finest wine vinegar you can find (sherry is often the best bet), and be sure to use dark Asian sesame oil made from toasted seeds (the Japanese brands are consistently superior). The cold-pressed sesame oil sold in health-food stores doesn’t have the flavor you need.
– 12 medium (about 3 ounces) dried, or 10 ounces fresh shiitake mushrooms.
– ½ cup dried tree ears (also called tree fungus or black fungus), optional.
– 20 dried tiger lily stems (optional).
– 1 quart meat or poultry broth, preferably brown.
– 1 cup (½-inch) cubed tender raw or cooked meat such as chicken, pork, duck, or beef(about ½ pound by weight).
– 3 tablespoons soy sauce.
– 1 teaspoon Asian sesame oil.
– 1 tablespoon cornstarch.
– One-half 10-ounce package firm Japanese tofu, cut into ⅓-inch cubes.
– ¼ cup sherry vinegar or other good wine vinegar, plus more to taste.
– 1 tablespoon freshly ground pepper.
– 1 egg, beaten.
– 1 green onion, white and 3 inches of the green, very thinly sliced.
Step 1:If using dried mushrooms, put them in a small heatproof bowl with boiling water to cover and soak for 1 hour. (You can also soak them overnight in cold water.) In separate bowls, soak the tree ears and lily stems in hot water for 10 minutes, or until softened.
Step 2:Lift the shiitake out of their soaking water and squeeze them, releasing the liquid into the bowl; discard liquid. Cut off the stems (save them for adding to broths) and slice or quarter the caps. Put the slices in a pot.
Step 3:Drain the tree ears and lily stems; pull the tree ears into small pieces,discarding any hard parts, and pull the stems into shreds. Add to the pot with the mushrooms, and pour in the broth. Bring to a gentle simmer and add the meat. In a small bowl or cup, whisk together the soy sauce, sesame oil, and cornstarch until smooth, and then whisk the mixture into the soup. Add the tofu, vinegar, and pepper. With the soup still at a gentle simmer, and while stirring constantly, add the egg in a thin, steady stream, pouring it in a circle. You want it to set in thin wisps throughout the broth. Add the green onion and season with salt. If you added raw meat, make sure the soup simmers for at least 3 minutes before serving.