Tom Kha Gai (Thai Coconut Chicken Soup)

About This Recipe

Tom Kha Gai — literally 'galangal chicken soup' — is Thailand's most famous coconut-based soup. Where tom yum is bold and tart, tom kha is silky and aromatic, built on the gentle, medicinal perfume of galangal (kha in Thai), lemongrass and kaffir lime leaves rather than the aggressive chilli-fish sauce base of its sibling. It is simultaneously comforting and complex, familiar and transporting. The soul of tom kha is the trio of fresh aromatics that no substitute can replace: galangal (a close relative of ginger with a pine-like, medicinal quality), fresh lemongrass (providing citrus and floral notes) and kaffir lime leaves (releasing a distinct, fragrant, double-lobed leaf oil). These are not meant to be eaten — they are infused into the coconut broth, then left in the bowl as flavour markers. Fish sauce provides the salt and umami depth that soy sauce cannot replicate. The secret to restaurant-quality tom kha is not boiling the coconut milk. A gentle simmer preserves the delicate fat emulsion and keeps the broth silky rather than grainy. Bird's eye chillies add heat; the lime juice, added at the very end, brightens the entire soup. In Thailand, tom kha is served in a clay pot and eaten alongside steamed jasmine rice — the classic combination.

Ingredients

Serves 4

• 400 mlfull-fat coconut milk
• 400 mlchicken stock
• 300 gboneless chicken breast or thigh(thinly sliced)
• 3 stalkslemongrass(bruised and cut into 3 cm pieces)
• 5 cm piecefresh galangal(or 3 cm ginger, thinly sliced)
• 6 leaveskaffir lime leaves(torn in half)
• 3 tbspfish sauce(to taste)
• 2 tbsplime juice(freshly squeezed)
• 1 tsppalm sugar or brown sugar
• 2 bird's eye chilliesbird's eye chillies(bruised — or to taste)
• 200 goyster mushrooms(or straw mushrooms)
• 3 tbspfresh coriander leaves(to garnish)
• 2 tbspthinly sliced spring onion(to garnish)

Instructions

1. 1

   Infuse the aromatics

   In a medium saucepan, combine chicken stock, lemongrass, galangal, kaffir lime leaves and bruised chillies. Bring to a gentle simmer over medium heat and cook for 5 minutes to infuse the broth.

2. 2

   Add coconut milk

   Pour in coconut milk and return to a gentle simmer — do not boil vigorously or the coconut milk will separate.

   Keep the heat at a calm simmer throughout. Boiling splits the coconut emulsion and makes the broth grainy.

3. 3

   Cook the chicken and mushrooms

   Add chicken slices and mushrooms. Simmer gently for 5–7 minutes until the chicken is just cooked through.

4. 4

   Season

   Add fish sauce and sugar. Taste and adjust — the broth should be savoury, with subtle sweetness. Remove from heat.

5. 5

   Finish with lime

   Stir in lime juice. The lime is added off heat to preserve its fresh, floral acidity.

   Never boil lime juice into a soup — it turns bitter. Add it at the end, off the heat.

6. 6

   Serve

   Ladle into bowls (leaving the lemongrass, galangal and kaffir lime leaves in the bowl as aromatics — they are not eaten). Garnish with fresh coriander and spring onion. Serve with steamed jasmine rice.

Variations

• •

  Tom Kha Het (mushroom): omit chicken and use a mix of oyster, shiitake and enoki mushrooms for a vegan version (substitute soy sauce for fish sauce).

• •

  Tom Kha Goong (prawn): substitute chicken with 300g raw prawns, peeled — cook for only 2–3 minutes.

• •

  Tom Kha Tofu: use extra-firm tofu and substitute fish sauce with soy sauce for a vegan version.

Storage

Refrigerate for up to 3 days. Reheat gently over low heat — do not boil. The lime juice flavour diminishes; add a fresh squeeze before serving reheated soup.

Frequently Asked Questions