To begin, prepare the key aromatics. Gently bruise the lemongrass stalks by pressing them with the flat side of a knife to release their flavour. Slice the galangal thinly, as this will help infuse the soup with its distinctive aroma. Tear the kaffir lime leaves in half to release their oils.

In a large saucepan, pour the coconut milk and chicken broth. Add the prepared galangal, lemongrass, and kaffir lime leaves. Heat the mixture over medium heat until it begins to simmer, allowing the flavors to infuse into the coconut milk for 10-12 minutes.

Once the broth is fragrant, add the chicken slices to the saucepan. Stir gently and cook the chicken for 5-6 minutes, or until it is opaque and cooked through. Keeping the soup at a gentle simmer will prevent the coconut milk from separating.

Add the sliced mushrooms and bird’s eye chilies to the pot. Let the mushrooms cook for 3-4 minutes until tender, which will enhance the soup’s texture and add an earthy flavour.

Season the soup with fish sauce, lime juice, and sugar, adjusting to taste. Fish sauce adds a salty depth, while lime juice balances the sweetness of the coconut milk. Taste the soup and make any adjustments as needed to achieve a balance of salty, sour, and slightly sweet flavors.

Allow the soup to simmer for another 2-3 minutes, ensuring that all ingredients are well incorporated. Avoid boiling, as this can cause the coconut milk to lose its creamy consistency.

Remove the saucepan from the heat. If desired, remove the larger pieces of lemongrass, galangal, and kaffir lime leaves for easier eating. These ingredients are for flavouring and not meant to be eaten directly.

Serve the Tom Kha Gai in individual bowls, garnished with fresh cilantro leaves. For added flavour and authenticity, offer additional lime wedges and sliced chilies on the side. This dish is traditionally enjoyed with steamed jasmine rice or as a standalone comforting soup.