Rockfish Tom Kha

Posted in Recipe Collections / Favorite Recipes: Thai, Persian, Korean, French, and More
Rockfish Tom Kha
Rockfish Tom Kha is a creamy, bright, aromatic Thai coconut soup built around delicate white fish. The broth is infused with lemongrass, galangal or ginger, lime, chiles, and herbs, then the rockfish is gently poached so it stays tender and flaky.

Ingredients

For the Broth:

  • 2 tablespoons neutral oil or coconut oil
  • 1 shallot, thinly sliced
  • 4 cloves garlic, sliced
  • 2-inch piece fresh galangal or ginger, thinly sliced
  • 2 stalks lemongrass, smashed and cut into 2-inch pieces
  • 4 makrut lime leaves, torn, optional
  • 1-2 Thai chiles, smashed or thinly sliced
  • 4 cups seafood stock or chicken stock
  • 2 cans full-fat coconut milk, 13.5 ounces each
  • 2 tablespoons fish sauce
  • 1 teaspoon soy sauce
  • 1-2 teaspoons palm sugar or brown sugar

For the Soup:

  • 8 ounces mushrooms, such as oyster, shimeji, or cremini
  • 1 to 1 1/2 pounds rockfish fillet, cut into large chunks
  • 1 small tomato, cut into wedges, or 1 cup halved cherry tomatoes
  • Juice of 2 limes, plus more to taste

For Garnish:

  • Fresh cilantro
  • Thai basil
  • Sliced scallions
  • Chili oil or chili crisp, optional
  • Lime wedges

Instructions

  1. Build the Aromatic Base: Heat the oil in a soup pot over medium heat. Add the shallot, garlic, galangal or ginger, lemongrass, makrut lime leaves if using, and chiles. Cook for 2-3 minutes, stirring often, until fragrant but not browned.

  2. Simmer the Broth: Add the stock and bring to a gentle simmer. Simmer for 15-20 minutes so the aromatics infuse the broth. Strain out the lemongrass, lime leaves, and large galangal or ginger slices for a smoother restaurant-style soup.

  3. Add Coconut and Seasoning: Reduce the heat to low. Stir in the coconut milk, fish sauce, soy sauce, and sugar. Taste and adjust until the broth is savory, creamy, lightly sweet, and aromatic.

  4. Cook the Mushrooms and Fish: Bring the soup back to a very gentle simmer. Add the mushrooms and cook for 3-4 minutes. Add the rockfish and poach gently for 4-5 minutes, until just flaky. Add the tomatoes during the final minute.

  5. Finish with Lime: Turn off the heat and stir in the lime juice gradually, tasting as you go. The soup should be bright and citrusy without becoming harsh.

  6. Garnish and Serve: Ladle into bowls and garnish with cilantro, Thai basil, scallions, chili oil or chili crisp, and extra lime wedges.

Creamy Coconut Soup for Delicate Fish

Rockfish works beautifully in Tom Kha because it is mild, flaky, and delicate. The key is to build a deeply aromatic broth first, then add the fish only at the end so it poaches gently instead of breaking apart.

For a more polished, restaurant-style version, strain the broth before adding the coconut milk. For a more rustic bowl, leave the lemongrass, galangal, and lime leaves in the pot and eat around them.

Makrut Lime Leaf Substitute

If you do not have makrut lime leaves, use lime zest, a few strips of lime peel, and extra cilantro stems or Thai basil. Add the peel while the broth simmers, then remove it before serving.

A bay leaf with lime zest can also add a little herbal depth, though it will not have the same floral citrus note.

Restaurant-Style Upgrades

Saute a small spoonful of red curry paste with the aromatics for extra depth and color. For texture, top the finished soup with crispy shallots, fried garlic, or toasted coconut.

Roasted kabocha squash or sweet potato also works well here, adding gentle sweetness against the lime and coconut.

Serving Ideas

Serve Rockfish Tom Kha with jasmine rice, sticky rice, cucumber salad, Thai fresh rolls, or roasted vegetables. A crisp riesling or cold lager pairs nicely with the coconut, lime, and chile.

Fish Variations

This recipe also works with halibut, cod, sablefish, snapper, shrimp, or scallops. Avoid boiling the soup after the seafood goes in; gentle heat keeps everything tender.