Tom Kha Soup Recipe

Prepare aromatics

Bruise the lemongrass stalks by cutting off the dry top and bottom, then smash the stalks lightly with the back of a knife and slice them into 2-3 pieces. Peel and slice the shallots thinly. If using fresh galangal, slice into 3 thin rounds. Tear the kaffir lime leaves into large pieces to release oils. Lightly crush the chilies (keep whole for less heat, halve for more).

In a large saucepan or stockpot, heat 1 tbsp vegetable oil over medium heat for 30 seconds. Add sliced shallots and sauté 1 minute until fragrant but not browned.

Add 6 cups of chicken or vegetable broth, bruised lemongrass pieces, galangal slices (or 1 tsp galangal powder), and kaffir lime leaves. Bring to a gentle simmer, then reduce heat to low and simmer uncovered for 10 minutes to infuse the broth.

After 10 minutes, stir in 2 cups coconut milk and return to a gentle simmer. Do not boil vigorously after adding coconut milk to prevent separation — keep at a gentle simmer.

Prepare mushrooms: clean and slice larger mushrooms, or leave small mushrooms whole. If using a tomato, cut into wedges. Slice green onions on the bias, and roughly chop cilantro leaves (reserve stems for garnish if desired).

If using chicken: thinly slice 8 oz chicken breast across the grain into bite-sized strips. If using shrimp: ensure they are peeled, deveined, and tails removed or left on per preference.

Raise the heat so broth returns to a gentle simmer (not a rolling boil). Add the mushrooms (and tomato, if using) and simmer 3–4 minutes until mushrooms begin to soften.

Add the protein: if chicken, add slices and simmer 4–5 minutes until cooked through (internal temperature 165°F/74°C). If shrimp, add and simmer 2–3 minutes until pink and opaque. Taste one piece to ensure doneness.

Turn heat to low. Remove and discard the lemongrass pieces, galangal slices (if used fresh), and any tough parts of kaffir lime leaves. Keep the infused coconut broth in the pot.

Stir in 3 tbsp fish sauce, 1 tsp soy sauce (optional), and 1 tsp palm sugar. Taste the soup: it should be a balance of salty (fish sauce), sour (lime), sweet (sugar), and spicy (chilies). Adjust fish sauce or sugar to taste.

Add 3 tbsp fresh lime juice gradually, stirring and tasting as you go until desired sourness is reached. If you prefer it hotter, slice one of the chilies thinly and add now; leave seeds for more heat.

Season with 1 tsp ground white pepper and stir. If the coconut flavor is too rich, add up to 1/2 cup additional broth to taste.

Turn off the heat. Ladle the soup into bowls and garnish with sliced green onions and chopped cilantro leaves.