This is one of the tastiest soup recipes I have! It is fresh and flavorful and will be an absolute hit at your next dinner party! This recipe is originally from Cooks Illustrated. As always, the secret to making this soup as tasty as possible is to use homemade chicken stock if you can.
You can make the soup more or less spicy by adjusting the amount of red curry paste. Do not overcook the chicken as it will become tough after too long.
Thai Chicken Soup
1 tsp olive oil
3 lemongrass stalks (bottom 5 inches or so, tough outer leaves removed, and sliced thinly)
3 shallots, chopped
8 sprigs fresh cilantro, chopped
3 TBSP fish sauce
4 cups chicken broth
2 14oz cans coconut milk, well shaken
1 TBSP sugar
8 oz white mushrooms, cut into 1/4" slices
1 lb boneless, skinless chicken breast, halved lengthwise and sliced into 1/8" pieces (see note below)
3 TBSP fresh lime juice (2-3 limes approx)
2 tsp thai red curry paste
1/2 cup fresh cilantro leaves
2 serrano chiles, sliced thinly
2 scallions, sliced thin
1 lime, cut into wedges
Heat oil in large saucepan over med heat. Add lemongrass, shallots, cilantro, and 1 TBSP fish sauce; cook, stirring frequently, until just softened, 2-5 mins. Do not brown veggies. Stir in chicken broth and 1 can coconut milk; bring to simmer over high heat. Cover, reduce heat to low, and simmer until flavors have blended, 10 mins. Remove from heat and strain broth. Wipe out pan, return strained broth to pan, and return pan to stove over med-high heat.
Stir in remaining can of coconut milk and sugar into broth mixture and bring to simmer. Reduce heat to medium, add mushrooms and cook until just tender, 2-3 mins. Add chicken slices and cook, stirring constantly, until no longer pink, 1-3 mins. Remove soup from heat.
Combine lime juice, curry paste, and remaining 2 TBSP fish sauce in small bowl. Add to soup.
Ladle soup into bowls and garnish with cilantro, chiles, and scallions. Serve immediately with a lime wedge.
Note: The thinner you can slice the chicken, the faster it will cook and the more tender it will be. You can put the chicken breast in the freezer to firm it up and it will make slicing thinly easier.