• 2 stalks fresh lemongrass
• 1.2 litres (2 pints) homemade vegetable stock or store-bought fresh stock
• 2 tablespoons coarsely chopped fresh galangal root or 1 tablespoon finely chopped fresh ginger
• 4 fresh kaffir lime leaves or 2 teaspoons lime zest
• 110 g (4 oz) button mushrooms
• 175 g (6 oz) firm beancurd
• 110 g (4 oz) large fresh red or green Thai chillies
• 175 g (6 oz) fresh baby corn
• 1 teaspoon salt
• ¼ teaspoon freshly ground pepper or black pepper
• 2 tablespoons light soy sauce
• 2 tablespoons lime juice
• 2 teaspoons chilli bean sauce

Garnish

• 2 spring onions, finely shredded
• handful fresh coriander leaves

Peel the lemongrass to the tender whitish centre and crush with the flat of a knife. Then cut into 7.5 cm (3 in) pieces.

In a large saucepan, bring the stock to a simmer and add the lemongrass, galangal and lime leaves. Turn the heat to low, cover and simmer for 25 minutes.

While the stock is simmering, prepare the vegetables. Slice the mushrooms. Cut the beancurd into 2.5 cm (1 in) cubes. Seed and slice the chillies. Split baby corn in half.

Remove the lemongrass, galangal and leaves from the stock with a slotted spoon and discard. Then add the salt, pepper, soy sauce, lime juice and chilli bean sauce. Simmer for another 3 minutes. Now add the vegetables, cover the pot and simmer for 10 minutes or until the vegetables are cooked through.

Finally, stir in the spring onions and fresh coriander leaves. Ladle into a large soup tureen or individual bowls and serve immediately.