- 1 tablespoon cooking oil
- 6 scallions including green tops, chopped
- 4 cloves garlic, minced
- 2 teaspoons chopped fresh ginger
- 1/4 cup soy sauce
- 1/4 teaspoon dried red pepper flakes
- 3 1/2 cups water
- 3 1/2 cups canned low-sodium chicken broth or homemade stock
- 4 carrots, cut diagonally into 1/4-inch slices
- 3/4 pound napa (Chinese) cabbage, leaves shredded
- 3/4 teaspoon salt
- 1 small head bok choy, stalks halved lengthwise and cut crosswise into 1/2-inch pieces, leaves shredded
- 1 lemon, zested
- 2 tablespoons lemon juice
- 1/4 pound vermicelli
- 1 1/2 teaspoons Asian sesame oil
- In a large saucepan, heat the cooking oil over moderately low heat. Add the scallions, garlic, and ginger and cook, stirring occasionally, until fragrant, about 1 minute. Add the soy sauce, red-pepper flakes, water, and broth and bring to a boil.
- Add the carrots to the broth and simmer for 5 minutes. Stir in the cabbage and salt and simmer for 5 minutes longer. Add the bok choy and lemon zest and simmer until the bok choy starts to soften, about 5 minutes. Stir in the lemon juice.
- Meanwhile, in a large pot of boiling salted water, cook the vermicelli until just done, about 9 minutes. Drain. Return the noodles to the pot and toss with the sesame oil. Put some noodles in each of four bowls and ladle the soup over the noodles.