Tom Yum Goong (Thai Hot and Sour Shrimp Soup)

Instructions

1. Peel and devein the shrimp, leaving the tails on, and refrigerate them. Keep the shells and heads.
2. Rinse the shells and heads, then simmer them in the water for 10 minutes. Strain through a sieve and discard the shells. Top up with water to about 1 liter (4 cups) of stock.
3. Return the stock to the pot and add the lemongrass, galangal, lime leaves and chilies. Simmer gently for 5 minutes so the herbs scent the broth.
4. Add the mushrooms and tomatoes and cook for 3 minutes, until the mushrooms soften.
5. Add the shrimp and cook for 2 to 3 minutes, just until they curl and turn pink. Do not let them boil hard or they will turn rubbery.
6. Take the pot off the heat. Stir in the fish sauce, the chili paste if using, and then the lime juice. Taste: the soup should be sharply sour, salty and hot.
7. Ladle into bowls, scatter with coriander and serve with steamed rice. The lemongrass, galangal and lime leaves are there for aroma, so eat around them.

Tips

• Fresh galangal and lemongrass are easy to find frozen in Asian shops. If you cannot find galangal, use a few thin slices of ginger and an extra lime leaf for a similar aroma.
• For the creamy version, stir 3 tablespoons of evaporated milk or coconut milk into the finished soup, along with a spoonful of roasted chili paste for color.