In its traditional form, this classic Lao soup is made with noodles rolled out and cut to order for each bowl. It is still excellent made with dried rice noodles. You can substitute fish, chicken, or pork for the beef, but rice noodles are an essential ingredient. The Lao like a considerable amount of lime juice in their food—here a range is given so that you can flavor the soup to your taste.
- 1 lemongrass stalk
- 1 tablespoon Asian sesame oil
- 1 tablespoon vegetable oil
- 2 tablespoons minced shallot
- 2 small (1-inch) fresh Asian chiles such as bird or Thai, thinly sliced
- 2 tablespoons minced galangal or fresh ginger
- 5 cups low-sodium chicken broth
- 1 tablespoon Asian fish sauce
- 2 whole star anise
- 1 (3-inch) cinnamon stick
- 1 teaspoon salt
- 1/4 teaspoon freshly crushed white peppercorns
- 2 small tomatoes, each cut into 8 wedges or 2 Tablespoons Tomato paste.
- 6 small scallions, thinly sliced
- 2 to 4 tablespoons fresh lime juice
- 1/2 pounds dried flat rice noodles
- 1 (1 pound) sirloin steak (about 1 inch thick)
- 3 (5 ounces) cups coarsely chopped spinach
- 1/4 cup coarsely chopped fresh mint
Discard any dry outer leaves from lemongrass and coarsely chop bottom third of stalk. Heat oils in a 5-qt. heavy pot over moderate heat until hot but not smoking, then cook shallot and chiles, stirring, until dark brown (be careful not to burn), 3 to 4 minutes. Add lemongrass and galangal and cook, stirring, 1 minute.
Add broth, fish sauce, star anise, cinnamon stick, salt, and white pepper and bring to a boil. Reduce heat and simmer 20 minutes. Pour through a fine sieve into another pot and discard solids. Add tomatoes, scallions, and lime juice and simmer until tomatoes are softened, about 10 minutes.
Bring a large pot of water to a boil for noodles. Trim fat from steak and season with salt and pepper. Heat a well-seasoned ridged grill pan over moderately high heat until hot, then grill steak 4 to 5 minutes on each side for rare. Let stand 5 minutes before slicing very thin.
Meanwhile, cook noodles in boiling water until tender, about 6 minutes, and drain. Divide among 4 large soup bowls and top with spinach and steak. Ladle soup over and sprinkle with mint.