- 1 (8 ounce) package dried Thai rice noodles
- 6 cups chicken broth
- 2 stalks lemongrass
- 1 boneless, skinless chicken breast
- 1 cup sliced cremini mushrooms
- 1 fresh red chile pepper, minced, or more to taste
- 1 (14 ounce) can coconut milk
- 2 tablespoons grated ginger
- 2 tablespoons fish sauce (optional)
- 1 tablespoon minced garlic
- 2 tablespoons lime juice
- 1 pinch white sugar, or to taste (optional)
- 1 lime, cut into wedges
- 3 green onions, sliced
- 1 small bunch fresh basil leaves, chopped
- Bring a large pot of water to a boil. Remove from heat, add noodles, and cover.
- Peel and discard tough outer leaves from lemongrass. Roughly chop pale inner stalk and transfer to a food processor; pulse until minced, 1 to 2 minutes.
- Bring chicken broth to a boil in another large pot. Add lemongrass, chicken, mushrooms, red chile pepper. Cook for 5 minutes. Reduce heat to medium; stir in coconut milk, ginger, fish sauce, and garlic. Simmer soup gently until an instant-read thermometer inserted into the chicken reads at least 165 degrees F (74 degrees C), 10 to 15 minutes.
- Transfer chicken to a cutting board; slice thinly and return to the pot. Stir in lime juice and sugar.
- Drain noodles and divide among serving bowls. Ladle soup on top. Garnish with a lime wedge, green onions, and basil.