Tom Kha Soup Recipe

Prepare aromatics

Bruise the lemongrass by hitting the stalks with the back of a knife, then cut into 2-3 inch pieces. Slice galangal (or ginger) 1/8" thick. Tear kaffir lime leaves into pieces to release oils. Thinly slice the shallot.

Simmer base

In a medium pot, heat 1 tsp vegetable oil over medium heat. Add sliced shallot and briefly sauté 1 minute until fragrant (do not brown). Add stock and 1 cup water, then add bruised lemongrass, sliced galangal, and torn kaffir lime leaves. Bring to a gentle simmer and let simmer uncovered for 10 minutes to infuse flavors.

Add coconut milk

Lower heat to medium-low, stir in coconut milk and warm through—do not bring the coconut milk to a rolling boil (simmer gently) for 3–4 minutes.

Add mushrooms and tomatoes

Add the sliced mushrooms and halved cherry tomatoes (if using) to the gently simmering broth. Continue to simmer 4–5 minutes until mushrooms are tender but not mushy.

Add chilis and green onions

Add the thinly sliced chilis and the white parts of the green onions. Simmer 1–2 minutes to release heat and aroma.

Cook chicken (if using)

If adding thinly sliced chicken, add it to the simmering broth after the mushrooms have softened. Simmer gently 3–5 minutes until the chicken is cooked through (internal temperature 165°F / 74°C).

Season soup

Remove the pot from heat. Stir in fish sauce, lime juice, and palm or brown sugar. Taste and adjust: add more fish sauce for saltiness, more lime juice for acidity, or a pinch more sugar to balance.

Final touches

Discard large pieces of lemongrass, galangal slices and any tough stems of kaffir leaves if preferred (you may leave small pieces for extra flavor). Add chopped cilantro and the green parts of the green onions. Stir gently.

Serve

Ladle soup into bowls and garnish with extra cilantro leaves and thinly sliced fresh chili if desired. Serve hot with lime wedges on the side.