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Thai Coconut Chicken Soup (Tom Kha Gai)

Thai Coconut Chicken Soup (Tom Kha Gai)

Thai Coconut Chicken Soup (Tom Kha Gai) with lemongrass, galanga and lime — creamy, bright and ready in 30 minutes, never hard-boiled.
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Prep Time 10 minutes
Cook Time 20 minutes
Total Time 30 minutes
Servings: 4 servings
Course: Soups
Ingredients Method Notes

Ingredients
  

For the broth:
  • 2 cans (13.5 ounces each) full-fat coconut milk, well shaken, divided
  • 2 cups low-sodium chicken broth
  • 3 stalks lemongrass, outer layers removed, cut into 2-inch pieces and lightly smashed
  • 1 piece fresh galanga (2 inches, about 1 ounce), sliced into thin coins — or the same amount of fresh ginger, sliced
  • 5 makrut lime leaves, torn in half and center ribs removed — or 1 teaspoon finely grated lime zest
  • 1 small shallot, thinly sliced
For the soup:
  • 1 pound boneless, skinless chicken breast, sliced thinly against the grain — or boneless, skinless chicken thighs, sliced
  • 8 ounces cremini mushrooms, sliced — or straw mushrooms, halved
  • 1 cup cherry tomatoes, halved
  • 2 to 3 Thai bird's eye chilies, lightly smashed — or 1/2 teaspoon red pepper flakes
  • 3 tablespoons fish sauce, plus more to taste
  • 2 teaspoons granulated sugar — or palm sugar
To finish and serve:
  • 1/4 cup fresh lime juice (from 2 to 3 limes), plus lime wedges for serving
  • 1/2 cup loosely packed fresh cilantro leaves
  • 2 green onions, thinly sliced
  • Steamed jasmine rice, for serving (optional)

Method
 

  1. Prep everything first (10 minutes): slice the chicken thinly against the grain and keep it cold in the fridge until its moment — thin slices poach evenly and stay tender. Smash the lemongrass pieces with the flat of a knife so they release their oils, slice the galanga into thin coins, tear the makrut lime leaves and remove their center ribs, slice the shallot and mushrooms, halve the cherry tomatoes, and smash the chilies. Juice the limes but set the juice aside — it does not go in until the very end. Tom Kha Gai cooks fast once the pot is on, so this 10 minutes of prep is what keeps the cooking calm.
  2. Infuse the broth (5 minutes): in a large pot or Dutch oven, combine 1 can of the coconut milk, all 2 cups of the chicken broth, the lemongrass, galanga, makrut lime leaves and shallot. Bring the mixture just to a gentle simmer over medium heat — small bubbles lazily breaking at the edges, never a rolling boil — and simmer for 5 minutes, until the broth smells deeply fragrant. Boiling coconut milk hard at this stage can split it and dull the aromatics, so lower the heat the moment it gets lively.
  3. Poach the chicken (8 minutes): add the sliced chicken in a single layer, stir once to separate the pieces, and keep the broth at that same gentle simmer for 8 minutes, until the chicken is cooked through, opaque all the way through and registers 165°F (74°C) on an instant-read thermometer. Thin slices poach quickly and gently here; a hard boil would toughen them, which is the second reason this soup never boils.
  4. Add the mushrooms and tomatoes (5 minutes): stir in the mushrooms, cherry tomatoes and chilies, and simmer gently for 5 minutes more, until the mushrooms are tender and the tomatoes have softened and slumped slightly but still hold their shape. Their juices loosen the broth a little and add a soft sweetness that balances the lime to come.
  5. Season the broth (2 minutes): stir in the second can of coconut milk, the 3 tablespoons of fish sauce and the 2 teaspoons of sugar, and warm everything through at a bare simmer for 2 minutes, until steaming hot again but not boiling. Taste now, before the lime: the broth should be savory and rounded. The fish sauce is the salt in this soup, so add a little more only if it truly tastes flat.
  6. Finish off the heat and serve: take the pot completely off the heat, wait a moment so the bubbling stops, then stir in the 1/4 cup of lime juice. Taste again and adjust — a little more lime for brightness, a little more fish sauce for depth. Fish out the lemongrass pieces, galanga coins and lime leaves if you like (they are aromatics, not garnish, and nobody enjoys chewing them). Ladle into 4 warm bowls, scatter the cilantro and green onions over the top, and serve right away with lime wedges and steamed jasmine rice on the side, if you like.

Notes

Never hard-boil the coconut milk, and add the lime juice off the heat.