ต้มข่ากุ้งTom kha kung

The lemongrass–galangal–coconut shrimp soup, and the dish that carries most of Thailand's kitchen aromatics in one bowl. Shrimp in a clear-but-silky broth built on bruised lemongrass, sliced galangal, kaffir lime leaf and chili, rounded with coconut milk and finished with fish sauce, lime and coriander at the stove.

Origin

Thai, Isan and central (ต้มข่า, tom kha)

Difficulty

2 / 5

Servings

3–4

Prep

15 min

Cook

20 min

Total

~35 min

Equipment

• A wide, heavy-bottomed pot — the calm-simmer logic of the braising article
• A wooden spoon or mallet, to bruise the lemongrass

Ingredients

• 3 (8 cm) lemongrass stalks, the fibrous outer layer peeled back and the core bruised loose
• 30 g (2 thumb) galangal (or, in a pinch, a 20 g piece of ginger, but the galangal is the right note), sliced thin
• 5 (35 g) kaffir lime leaves, the stems removed and the leaves torn
• 2 (15 g) bird's eye chilies (or more), sliced
• 900 ml (4 cups) water
• 300 ml (1¼ cups) coconut milk
• 40 ml (2⅔ tbsp) fish sauce
• 15 g (1 tsp) palm sugar
• 300 g (11 oz) large peeled shrimp, the vein removed
• 2 (90 ml) limes, the zest of half grated and the juice of both, divided
• 25 g (1 bunch) fresh coriander, chopped — for the bowl

Method

1. Prep the aromatics. Peel back the tough outer layer of the lemongrass and bruise the inner core with the back of a spoon or a mallet — you want the stalk loose, not chopped, so the oils release but the fiber stays out of the bowl. Slice the galangal thin. Tear the kaffir lime leaves, stems removed. This is the aromatics setup for a tom kha: whole and bruised, not minced, because they are meant to infuse and then be fished out, not to live in the soup.
2. The clear base. Into the cold water: the bruised lemongrass, the sliced galangal, the torn kaffir lime leaves, and the sliced chilies. Bring to a gentle simmer on medium, then drop to the lowest heat that keeps the surface moving — the calm-simmer rule from the braising article — and let it go 5–8 min. You want the smell to fill the kitchen and the water to take on a faint, clean lemongrass-cloud color. This is the "clear broth" half of the dish, and it is done gently, not boiled.
3. The coconut. Pour in the 300 ml of coconut milk and stir to a pale, silky broth. Do not let this boil: if it does, the coconut oil separates and the broth goes greasy and split. A low, moving simmer is the ceiling you're cooking under.
4. Balance the broth. In with the fish sauce, the palm sugar, and the grated lime zest. Taste the broth now — it should hit sour (from the later lime), salty second (the fish sauce), sweet to carry it, with the lemongrass and galangal underneath. The balance is set here, before the shrimp, so you can adjust it against the broth and not against the protein.
5. The shrimp. Lower the shrimp in, one by one or in a loose handful, and let them cook 2–3 min, just until they turn from grey-pink to a clean coral and tighten up. Any longer and they go rubbery, and a rubbery shrimp in a tom kha drags the whole bowl down. Off the heat.
6. Finish at the bowl. Into each bowl: the shrimp, the broth with the whole aromatics (leave them in for the drink at the table — they're the smell), a scattering of the chopped coriander, and the juice of the lime wedges squeezed over the top just before you eat. The lime at the bowl is the acid that most home versions are missing, and it is what turns a "shrimp in coconut broth" into a tom kha.

What to serve with it

This is the "soup" of a Thai table — the one that comes with the rice and stands on its own as a light, fragrant bowl. It pairs with anything that is plain and starchy: plain jasmine rice (the rice article) is the classic, and a khao pad (fried rice) is also right, the two of them sharing the fish-sauce-and-garlic axis. A som tum (green papaya salad) is the sharp, raw counterpoint to the cooked, fragrant soup, and the two of them together cover the whole table.