Salmon Tom Yum Soup Recipe

Prepare aromatics

Smash the lemongrass stalks with the flat side of a knife and cut into 2–3 pieces each. Thinly slice the galangal into 1/8-inch rounds. Peel and halve the shallot. Smash the garlic cloves. Slightly tear the kaffir lime leaves to release oils.

Sauté aromatics (optional)

In a medium soup pot over medium heat, warm 1 tsp neutral oil. Add sliced galangal, shallot and smashed garlic and sauté 1–2 minutes until fragrant but not browned. This step deepens flavor but can be skipped for a fresher broth.

Simmer broth

Add 6 cups water and 2 cups stock to the pot. Add the prepared lemongrass, galangal, kaffir lime leaves and whole Thai red chilies. Bring to a gentle boil, then reduce heat and simmer uncovered for 12–15 minutes to infuse the aromatics.

Remove the pot from heat briefly. Stir in 3 tbs fish sauce, 1 tbs nam prik pao (or tomato paste), and 1 tsp palm or brown sugar. Taste the broth and adjust: it should be balanced salty, sour and a touch sweet (you will add lime juice later). If using coconut milk for a creamier tom yum, stir it in now and return to a gentle simmer.

Add mushrooms and tomato wedges to the simmering broth. Cook 2–3 minutes until mushrooms begin to soften and tomatoes release some juice.

Lower the heat so broth is barely simmering. Gently slide the salmon pieces into the soup in a single layer. Poach for 3–4 minutes until salmon is just cooked through and opaque (internal temperature ~125–130°F / 52–54°C for medium). Avoid vigorous boiling so the fish stays tender.

Turn off heat. Stir in 3 tbs fresh lime juice, 1/2 tsp salt (adjust to taste), and 1/4 tsp ground white or black pepper. Add sliced scallions and most of the chopped cilantro, reserving some for garnish. If you like extra heat, slice 1 bird's eye chili and add now.

Ladle soup into bowls, making sure each bowl gets both mushrooms and salmon. Garnish with remaining cilantro and extra scallion. Serve hot with steamed jasmine rice on the side if desired.

If you prefer a more pronounced sourness, add up to 1 tbs additional lime juice. Adjust fish sauce for saltiness. For a vegetarian version, substitute tofu for salmon and use vegetable stock.