Seafood Tom Yum Recipe

Prepare aromatics

Smash the lemongrass stalks with the back of a knife and trim ends; cut into 2–3 pieces each. Peel and lightly crush the shallots and garlic. Slice galangal into 4–6 thin slices. Rinse and tear the kaffir lime leaves into a few pieces to release oils. Halve the tomatoes into quarters. If you prefer less heat, halve or remove seeds from the bird's eye chiles; leave them whole for more flavor.

Build the broth

In a medium-large pot, heat 1 tablespoon vegetable oil over medium heat. Add shallots and garlic and sweat for 1 minute until fragrant (do not brown). Add smashed lemongrass, sliced galangal, kaffir lime leaves, and chiles; stir for 30 seconds. Pour in 6 cups stock and 1 cup water and raise heat to high. Bring to a gentle boil, then reduce to a simmer. Add quartered tomatoes and simmer uncovered for 8–10 minutes to infuse the broth.

Strain (optional)

For a clearer broth, strain out the solids through a fine-mesh sieve into a clean pot, pressing to extract liquid. If you prefer a more rustic soup, leave aromatics in the pot and remove larger pieces before serving.

Prepare seafood

While broth simmers, pat shrimp, squid, and fish dry and season lightly with a pinch of salt. Slice mushrooms, chop cilantro (reserve some leaves for garnish), and slice green onions on the bias.

Cook vegetables and seafood

Bring the infused broth back to a gentle boil. Add mushrooms and simmer 2–3 minutes until they begin to soften. Add squid and fish pieces and simmer 2–3 minutes more. Finally add shrimp and cook for 2–3 minutes until pink and opaque (shrimp cook quickly — do not overcook). Taste the broth for seasoning before finishing.

Season the soup

Turn off the heat or lower to the lowest setting. Stir in fish sauce (3 tbs), tamarind paste (1 tsp, if using), sugar (1 tsp), and 1 tablespoon of Thai chili paste (if using). Stir and taste. Add fresh lime juice in 3–4 additions (about 4 tbs total), tasting as you go to reach the characteristic bright sourness. Adjust fish sauce or lime to balance salty-sour-sweet.

Finish and serve

Ladle soup into bowls, distributing seafood and mushrooms evenly. Scatter chopped cilantro and sliced green onions over the top. If desired, garnish with extra torn kaffir lime leaf, a few thin slices of fresh chili, or a wedge of lime. Serve immediately with steamed jasmine rice or as a starter. Leftovers keep in the refrigerator for up to 2 days; gently reheat over low heat (avoid boiling to prevent seafood overcooking).