10 large shiitake mushrooms (about 4 ounces), stems discarded and caps
1 large garlic clove, thinly sliced
1 1/2 teaspoons finely grated fresh ginger
4 1/2 cups chicken stock or low-sodium broth
1/2 pound pork tenderloin, cut into 2-by- 1/2-inch strips
1 1/2 tablespoons cider vinegar
1 1/2 teaspoons soy sauce
1 teaspoon chile-garlic sauce or hot sauce
1 cup snow peas, thinly sliced lengthwise
3 scallions, thinly sliced
1/2 teaspoon cornstarch dissolved in 1 tablespoon cold water
1 teaspoon Asian sesame oil
Soak the noodles in a bowl of hot water until pliable, about 5 minutes.
Meanwhile, in a large saucepan, heat the oil until shimmering. Add the shiitake and cook over high heat, stirring occasionally, until lightly browned, 2 to 3 minutes. Add the garlic and ginger and cook, stirring, for 30 seconds. Add the stock and bring to a boil.
Drain the noodles, add them to the saucepan and cook over moderate heat just until tender, about 3 minutes. Add the pork, vinegar, soy sauce and chile-garlic sauce and simmer until the pork is nearly cooked through, about 2 minutes. Add the snow peas, scallions and cornstarch mixture and cook until the vegetables are crisp-tender, about 1 minute. Stir in the sesame oil and season with salt. Ladle the soup into bowls and serve.