Tom kha gai is the creamy Thai coconut soup: galangal, lemongrass, and kaffir lime leaves infused gently into coconut milk, with chicken and mushrooms, seasoned with fish sauce and a little sugar, and finished with lime juice off the heat. It is rich but not heavy, sour but not sharp.
Ingredients
Serves 4.
- 2 cans (13.5 oz each) coconut milk, well shaken
- 1 lb (450 g) boneless, skinless chicken thighs, cut into bite-size pieces
- 3 stalks lemongrass, tough outer layers removed, cut into 2-inch pieces and smashed
- 1 thumb-size piece fresh galangal, thinly sliced
- 5 kaffir lime leaves, torn
- 1 cup sliced mushrooms (straw, button, or oyster)
- 2 Thai bird’s eye chiles, sliced (to taste)
- 2 tbsp fish sauce, plus more to taste
- 1 tbsp sugar (palm or granulated)
- 3 tbsp fresh lime juice, added off the heat
- Cilantro leaves, for serving
For serving: cooked jasmine rice.
Method
- Pour about half the coconut milk into a medium saucepan over medium heat. Add the galangal, lemongrass, and kaffir lime leaves.
- Warm gently — bring just to the edge of a simmer, not a rolling boil. Let the aromatics infuse 8 minutes, stirring occasionally and scraping the bottom so the coconut milk does not scorch.
- Add the chicken pieces. Keep the heat at a gentle simmer and cook 5 minutes, until the chicken is cooked through to 165°F internal with no pink.
- Add the mushrooms and chiles; simmer 2 minutes more until the mushrooms are tender.
- Stir in the remaining coconut milk, the fish sauce, and the sugar. Warm through gently — do not let it come to a hard boil.
- Take the pot off the heat. Stir in the lime juice; taste and adjust fish sauce, sugar, and lime to balance. Serve in bowls topped with cilantro, with jasmine rice alongside. Leave the woody lemongrass, galangal slices, and lime leaves in the pot or pushed aside in the bowl — they are flavoring, not food.
Tips and ingredient notes
- Galangal vs. ginger — the honest version: galangal is piney, citrus-sharp, and floral; ginger is warm, sweet, and pungent. They are related rhizomes, not flavor twins. If you cannot find galangal (Asian markets usually carry it fresh or frozen), you can finish the soup with ginger — but the result is a ginger-coconut chicken soup, a different flavor, not tom kha gai as such.
- Coconut milk behavior: coconut milk is an emulsion that can split or curdle with aggressive boiling. Bring it up gently, simmer (do not hard-boil), and stir. Full-fat canned coconut milk gives the creamiest result; do not use sweetened coconut cream.
- Kaffir lime leaves: tear before adding to release oils. Dried leaves are a weaker substitute.
- Chicken cut: thighs are more forgiving of extra simmering time than breast.
- Sugar: palm sugar is the classic; brown or granulated sugar works. The amount is small and balance-driven — start with 1 tbsp.
Storage and food safety
Allergen note: contains fish (fish sauce). Chicken must reach 165°F (74°C) internal temperature with no pink (FoodSafety.gov). Serve within 2 hours; refrigerate leftovers promptly and reheat until steaming hot — warm gently, do not hard-boil.