Smoked Mackerel and Tomato Soup from Thai Food and Cooking by Judy Bastyra and Becky Johnson

Ingredients

• small bunch fresh chives or spring onions (scallions), to garnish
• 1 litre/1¾ pints/4 cups vegetable stock
• 1 lemon grass stalk, finely chopped
• 5 cm/2 in piece fresh galangal, finely diced
• 4 shallots, finely chopped
• 200 g/7 oz smoked mackerel fillets
• 4 tomatoes
• 5 ml/1 tsp palm sugar or light muscovado (brown) sugar
• 45 ml/3 tbsp thick tamarind juice, made by mixing tamarind paste with warm water
• 2 garlic cloves, finely chopped
• 2 1/2 ml/½ tsp dried chilli flakes
• 15 ml/1 tbsp Thai fish sauce