Chicken in Coconut Milk Soup

Tom kha gai translates to “chicken in galangal soup," and that root is the whole point. Galangal looks like ginger but tastes nothing like it. It’s piney, citrusy and slightly soapy in the best way, and it’s the defining flavor of this iconic Thai soup. No galangal, no tom kha. Don’t substitute fresh ginger and call it a day.

The technique is simple but particular. The aromatics (galangal, lemongrass, kaffir lime leaves) infuse the coconut-and-stock base for 20 minutes, then get strained out so you’re not chewing on tough stalks. The chicken cooks for just 2 minutes in the strained broth (it’s poaching, not boiling), which keeps the meat silky instead of stringy.

Fish sauce, lime juice, chiles and fresh cilantro go in at the end. Each one is a finishing ingredient: salt, acid, heat, herbs. The balance of those four is what every Thai cook chases, adjusting at the end of cooking so the soup tastes bright and complete.

Pro Tips

• Bruise the lemongrass stalks with the back of a heavy knife before cutting into 2-inch pieces. Crushing the fibers releases the essential oils that flavor the broth.
• Use Thai galangal if you can find it (Asian markets stock it fresh or frozen). Dried galangal works but lacks the brightness of fresh.
• Tear the kaffir lime leaves slightly before adding to release their oils. Whole leaves contribute almost nothing.
• Add lime juice off the heat. Boiling kills the fresh citrus brightness and turns the lime flavor flat and bitter.
• Adjust salt with fish sauce, not table salt. Real tom kha gets all its salinity from fish sauce, and that’s what gives the broth its proper savory depth.

Variations

• Add 1 cup of mushrooms (oyster, straw or button), sliced, with the chicken for a more substantial bowl.
• Use shrimp or firm tofu in place of chicken for a different protein. Shrimp need only 1 to 2 minutes of poaching.
• Stir in 1 teaspoon of palm sugar or brown sugar for a slightly sweeter version that balances the heat from the chiles.