Spicy Short Rib Soup (Tom Saep)

Ingredients

• 1 kg (2¼ lb) beef short ribs, cut into 5 cm (2 in) pieces
• 1.5 litres (6 cups) water
• 3 stalks lemongrass, bruised and cut in 5 cm lengths
• 5 slices galangal (or ginger, see Notes)
• 4 makrut lime leaves, torn (or 1 tsp finely grated lime zest, added with the lime juice)
• 4 shallots, halved
• 3 tbsp fish sauce, plus more to taste
• 2 tbsp lime juice
• 1 to 2 tbsp Thai chilli flakes (or red pepper flakes), to taste
• 1 tbsp toasted sticky rice powder (optional)
• 1 handful each of cilantro, sliced scallion and saw-tooth herb or mint

Steps

1. Boil the ribs in water to cover for 5 minutes, then drain and rinse them. This keeps the broth clear.
2. Return the ribs to a clean pot with the 1.5 litres of water, lemongrass, galangal, lime leaves and shallots. Bring to a boil over high heat, then reduce to a gentle simmer.
3. Skim any foam in the first 10 minutes. Cover partly and cook for 2 hours, until the meat is tender and pulls from the bones.
4. Fish out the lemongrass and galangal if you like, or leave them in for people to push aside.
5. Stir in the fish sauce and chilli flakes. Simmer for 5 minutes, then take the pot off the heat.
6. Add the lime juice and the rice powder, if using, which gives a nutty fragrance and slight body.
7. Taste. The soup should be hot, sour and salty in equal measure; adjust with more fish sauce or lime. Ladle into bowls and top with the herbs.

Notes

• Rice powder: toast 1 tbsp raw sticky rice in a dry pan over medium heat until golden, about 4 minutes, then grind. No sticky rice? Jasmine rice works.
• Heat: start with 1 tbsp of chilli flakes and add more at the table.
• Can't find galangal? Use 1½ times the amount of fresh ginger (about 7 slices) and add an extra squeeze of lime at the end; the soup will be a little sweeter and less piney.
• Serving: with steamed or sticky rice.
• Slow cooker: blanch the ribs, then cook with the water, lemongrass, galangal, lime leaves and shallots on low 8 hr or high 4 to 5 hr. Add the fish sauce, chilli and lime at the end.
• Make ahead: fridge 3 to 4 days; freezes 3 months. Reheat to steaming hot and add the lime juice and fresh herbs afterwards.