Thailand; tom yum is central to Thai culinary identity; the soup is believed to have been part of Thai cooking for centuries, documented in royal cuisine as well as street food contexts.
Tom yum — Thailand's hot-and-sour soup — is traditionally made with seafood or chicken, but its flavour framework is built entirely on plant-based aromatics: lemongrass, galangal, kaffir lime leaves, lime juice, and chilli. The vegan version swaps fish sauce for soy sauce (or a soy-mushroom combination), uses mushrooms (oyster, shiitake, straw mushrooms) as the main protein, and achieves the characteristic complexity through the aromatic base alone. What makes tom yum extraordinary is the intensity and precision of its aromatics — lemongrass is bruised, not chopped; galangal is sliced but not meant to be eaten; kaffir lime leaves are torn to release their oils. These are simmered briefly in the broth (5–7 minutes maximum) to extract their volatile compounds, then the soup is finished quickly. Tom yum is not a slow-simmered dish; it is assembled rapidly and served at peak brightness.
Bruised lemongrass releases intense citral aroma; galangal adds pine-camphor notes distinct from ginger; torn kaffir lime leaves create bright floral volatiles.
Fail: Short simmer (10-15 min max) preserves aromatic oils. Over-simmering kills complexity. Galangal non-negotiable—ginger substitution ruins the soup's identity.
Short simmer (10-15 min max) preserves aromatic oils. Over-simmering kills complexity. Galangal non-negotiable—ginger substitution ruins the soup's identity.
- 1 litre vegetable stock
- 400ml coconut milk (full fat)
- 3 stalks fresh lemongrass, bruised
- 40g fresh galangal, sliced
- 4 kaffir lime leaves, torn
- 150g oyster mushrooms, torn
- 100g firm tofu, cubed
- 2 Thai bird's eye chillies, crushed
- 45ml fish sauce substitute (tamari or soy sauce)
- 30ml fresh lime juice
- 15g fresh coriander, chopped
- Bring vegetable stock to a simmer in a large pot; add lemongrass, galangal, and kaffir lime leaves.
- Simmer 5 minutes uncovered to infuse flavours; strain solids, return liquid to pot.
- Stir in coconut milk and bring to a gentle simmer; add mushrooms and tofu.
- Simmer 3 minutes; add bird's eye chillies and tamari.
- Remove from heat; finish with lime juice and fresh coriander. Taste and adjust seasoning.
- Toasted dried chillies (prik haeng) added to the broth give a smoky, deep heat that complements the fresh chilli garnish
- For maximum clarity: strain the broth through a fine sieve after simmering the aromatics before adding mushrooms — removes all fibrous material and produces the clear, amber broth of professional tom yum
- Nam prik pao (roasted chilli paste) stirred into the finished soup adds the complex, slightly smoky note characteristic of tom yum kung (prawn version) — use sparingly