Tom Yum
A hot-and-sour mushroom broth built on bruised lemongrass, galangal and lime leaf, with the lime juice going in only at the very end.
- Prep
- 15m
- Cook
- 20m
- Total
- 35m
- Serves
- 4
- Effort
- Easy
Method
Tap a step number to mark it done. Tap an ingredient once for got it, twice for need it.
| 1.2 litres | Bruise the aromatics and steep them in simmering stock 12m Crush lemongrass with the flat of a knife until it splinters — whole stalks give you almost nothing. | Simmer the mushrooms and tomato in the aromatic broth for 6 minutes 8m Aromatics stay in the bowl. They are not eaten, but fishing them out costs you their perfume. | Off the heat, stir in lime juice and coriander and taste for balance 2m Sour, salty, hot, faintly sweet, in that order of prominence. Adjust before it leaves the pan. | |
| 3 stalks | ||||
| a 5 cm piece | ||||
| 6 | ||||
| 3 | ||||
| 3 | ||||
| 300 g | ||||
| 200 g | ||||
| 6 | ||||
| 3 tbsp | ||||
| 2 tsp | ||||
| 5 tbsp | ||||
| a large handful | ||||
| 2 tbsp | ||||
-
Bruise the aromatics and steep them in simmering stock
12m- vegetable stock 1.2 litres
- lemongrass 3 stalks
- galangal a 5 cm piece
- kaffir lime leaves 6
- coriander roots 3
- shallots 3
Crush lemongrass with the flat of a knife until it splinters — whole stalks give you almost nothing.
-
Simmer the mushrooms and tomato in the aromatic broth for 6 minutes
8m- from 1 Bruise the aromatics and steep them in simmering stock
- oyster mushrooms 300 g
- cherry tomatoes 200 g
- bird's eye chillies 6
- light soy sauce 3 tbsp
- palm sugar 2 tsp
Aromatics stay in the bowl. They are not eaten, but fishing them out costs you their perfume.
-
Off the heat, stir in lime juice and coriander and taste for balance
2m- from 2 Simmer the mushrooms and tomato in the aromatic broth for 6 minutes
- lime juice 5 tbsp
- coriander a large handful
- nam prik pao (optional) 2 tbsp
Sour, salty, hot, faintly sweet, in that order of prominence. Adjust before it leaves the pan.
Why the lime goes in last
Citric acid is stable, but the aroma of lime is not — the terpenes that make it smell like lime are volatile and start leaving the pot within a minute of heating. Boil the juice and you keep the sourness while losing everything that made it worth using, which is exactly how tom yum ends up tasting merely acidic rather than bright. Adding it off the heat preserves the aroma. The same reasoning applies to the herbs: aromatics steep in the hot broth, but nothing fragrant ever gets a hard boil.
Notes
- Bruise the chillies rather than slicing them. You get the perfume and the heat stays civil; slice them and it climbs fast.
- Fish sauce is standard here. Soy plus a pinch more salt matches the savoury weight, and a teaspoon of white miso gets you closer still.
- For the milky version, stir in the chilli jam and 100 ml of coconut milk with the mushrooms.