Preparation

• Finely grate 1 tsp. of zest from the lemon and put in a small dish. Add the cilantro and ginger, and mix together. Cut the zested lemon in half and squeeze it to obtain 3 Tbs. of juice.
• Thinly slice two of the chile halves crosswise.
• In a large saucepan, bring the broth to a boil over medium-high heat. Add the lemon juice, noodles, fish sauce, and the 2 remaining chile halves to the boiling stock. Reduce the heat, cover, and simmer the soup until the noodles are almost cooked, about 3 min.
• Remove the chile halves. Stir in the chicken and chile slices and return to a boil. Remove the pan from the heat, making sure the chicken slices are just cooked through. Taste and add a touch more fish sauce, if you like. Divide the soup evenly among four serving bowls. Divide the cilantro mixture among the bowls, stir, and serve.