Seafood Tom Yum Soup Recipe

Prepare aromatics

Smash the lemongrass stalks with the back of a knife and trim tough ends; cut into 2-3 inch pieces. Peel and thinly slice the galangal. Tear the kaffir lime leaves once to release oils. Lightly crush the shallots and chilies to bruise them.

In a large pot, heat 1 tablespoon vegetable oil over medium heat. Add shallots and chilies and sauté 1 minute until fragrant but not browned to release aroma.

Add 6 cups water and 2 cups chicken or seafood stock to the pot. Stir in the lemongrass, galangal, and kaffir lime leaves. Bring to a gentle boil over high heat, then reduce to a simmer. Simmer uncovered for 10–12 minutes to infuse the broth.

While the broth simmers, clean and prepare the seafood: pat shrimp dry, slice squid into rings, and scrub mussels/clams. Halve mushrooms and cut tomatoes into wedges. Slice green onions and chop cilantro (reserve some leaves for garnish).

After the broth has simmered 10–12 minutes, strain out the larger pieces of galangal, lemongrass (if desired), and most of the kaffir lime leaves (you may leave 1–2 torn leaves if you like stronger flavor). Return the clear broth to the pot and bring back to a gentle simmer.

Add mushrooms and tomatoes to the simmering broth. Cook 2–3 minutes until mushrooms begin to soften and tomatoes start to release juices.

Add mussels/clams to the pot, cover, and cook 3–4 minutes until they open. Discard any that remain closed after cooking.

Add squid rings and shrimp. Simmer 2–3 minutes more until shrimp turn pink and opaque and squid is tender. Avoid overcooking seafood.

Lower heat to medium-low. Stir in 3 tablespoons fish sauce, 1 tablespoon Thai chili paste (nam prik pao), and 1 teaspoon light brown sugar. Taste the broth and adjust seasoning: add more fish sauce for saltiness or a touch more sugar if too sharp.

Remove the pot from heat. Stir in 4 tablespoons fresh lime juice and 1/2 teaspoon sea salt (or to taste). If using, add 1/4 cup concentrated shrimp stock for extra umami and blend gently.

Add sliced green onions and most of the chopped cilantro into the soup. Let sit 1 minute to wilt herbs. Taste and adjust lime, fish sauce, or chili paste as desired.

Ladle the soup into bowls, garnish with remaining cilantro leaves and additional thinly sliced chilies or lime wedges if desired. Serve immediately with steamed jasmine rice or on its own.