Tom Yum Soup with Prawns

This tom yum goom is the classic hot-and-sour Thai soup, built on a fragrant broth of lemongrass, galangal, kaffir lime and chilli. Plump prawns and fresh mushrooms simmer briefly so everything stays tender, then a final hit of fish sauce and lime juice sharpens the whole bowl.

Tom yum is Thailand’s most famous soup for good reason: it lands hot, sour, salty and fragrant all at once, yet comes together in one pot. The trick is a quick aromatic broth and prawns that barely simmer, so they stay sweet and juicy. Balance it to your own taste at the end and serve steaming.

Ingredients

• 1.2 litres chicken or fish stock
• 3 stalks lemongrass — bashed and cut into 5cm lengths
• 6 slices galangal — or fresh ginger if unavailable
• 5 kaffir lime leaves — torn; sub zest of 1 lime
• 3-4 small red Thai chillies — lightly crushed, to taste
• 400 g raw king prawns — peeled, tails on, deveined
• 200 g chestnut or oyster mushrooms — halved
• 3 tbsp fish sauce — plus more to taste
• 3 tbsp lime juice — freshly squeezed
• 2 tbsp Thai roasted chilli paste (nam prik pao) — optional but authentic
• 6 cherry tomatoes — halved
• 1 tsp caster sugar
• 1 small handful coriander leaves — to garnish

Method

1. Pour the stock into a large saucepan and bring to a gentle boil. Add the lemongrass, galangal, torn lime leaves and crushed chillies. Simmer for 5 minutes so the broth turns deeply fragrant.
2. Stir in the mushrooms and cherry tomatoes and simmer for 3 minutes, until the mushrooms soften and the tomatoes start to collapse.
3. If using, stir in the nam prik pao and the sugar until dissolved, giving the broth a mellow, slightly smoky depth.
4. Add the prawns and simmer gently for 3-4 minutes, just until they turn pink and opaque and are cooked through with no grey translucency in the centre. Do not let it boil hard or they will toughen.
5. Take the pan off the heat. Stir in the fish sauce and lime juice, then taste: it should be boldly sour, salty and a little hot. Adjust with more fish sauce, lime or sugar until balanced.
6. Ladle into bowls, making sure everyone gets prawns and mushrooms. Scatter with coriander and serve piping hot. Leave the woody lemongrass and galangal in the bowl as aromatics rather than eating them.

Serve it with

• steamed jasmine rice
• a second Thai dish like green curry
• extra lime wedges
• sliced fresh chilli in fish sauce
• prawn crackers

Why this works

Adding the fish sauce and lime off the heat keeps their aroma fresh and sharp instead of cooking away, which is what gives real tom yum its lively hot-and-sour lift.

Common swaps

• Swap prawns for sliced chicken thigh or firm white fish; simmer chicken a few minutes longer until cooked through.
• No galangal? Use fresh ginger for a warmer, slightly different note.
• For tom yum nam khon (creamy style), stir in 3 tbsp coconut milk or evaporated milk at the end.
• Vegetarian: use vegetable stock, swap fish sauce for light soy or a vegan fish sauce, and add tofu and extra mushrooms.

Common mistakes to avoid

• Boiling the prawns hard or too long, which makes them rubbery; a gentle 3-4 minute simmer is plenty.
• Adding lime juice while the pan is on high heat, which dulls its bright sourness.
• Under-seasoning: tom yum should be assertively sour and salty, so keep tasting and adjusting at the end.
• Eating the lemongrass and galangal; they flavour the broth but are too woody to chew.

Storage, freezing & reheating

Storage: Cool leftovers quickly and refrigerate in a sealed container for up to 2 days. The prawns will firm up slightly on reheating.

Reheating: Reheat gently on the hob until piping hot, without letting it boil vigorously, then refresh with a squeeze of lime before serving.

Allergen notes: contains Crustaceans, Fish. Always check individual product labels.

Estimated nutrition

Per serving, estimated from typical ingredient values — not a substitute for precise dietary calculation.