Tom Saap — Isaan Spicy Pork Bone Soup / ต้มแซ่บ

Ingredients

• 800 g Pork spare ribs, cut into 4–5 cm sections
• 200 g Pork knuckle, bone-in, cut into chunks
• 100 g Tripe, cleaned, blanched separately before use
• 2 litres Water
• 3 stalks Lemongrass, bruised, cut into 5 cm lengths
• 30 g Galangal, sliced into coins
• 6 leaves Kaffir lime leaves, torn
• 8 Bird's eye chillies, bruised
• 3 tbsp Pla raa (fermented freshwater fish), strained of solids if preferred
• 3 tbsp Lime juice, freshly squeezed, added off heat
• 1 tsp Dried chilli powder
• 2 tbsp Toasted rice powder (khao khua), traditional finishing element

Method

1. 1
   Clean the tripe thoroughly and blanch in a separate pot of boiling water for 10 minutes. Drain, cut into bite-sized pieces, and set aside. The blanching water is discarded. The tripe is ready when it no longer carries a raw, sharp smell.
2. 2
   Place the pork ribs and pork knuckle in a large pot with the 2 litres of water. Bring to the boil, skim the grey foam from the surface, then reduce to a steady simmer. Add the lemongrass, galangal, kaffir lime leaves, bird's eye chillies, and the blanched tripe. Simmer, partially covered, until the pork is completely tender — the meat should yield without resistance and begin to pull from the bone; the broth will have taken on visible body from the collagen.
3. 3
   This is where the dish lives or dies. Remove the pot from direct heat or reduce to the lowest possible flame. Stir in the pla raa and the dried chilli powder. Then add the lime juice. Taste immediately: the broth must be aggressively sour, distinctly savoury from the fermented fish, and fiercely hot. Adjust pla raa for depth and lime for sharpness — the acid must be bright and immediate, not flat. If either note is muted, the soup has not reached its character.
4. 4
   Finish by stirring in the toasted rice powder (khao khua). The powder disperses through the broth, adding a faint nuttiness and a very slight body. Ladle into deep bowls and serve immediately alongside sticky rice. The broth surface should carry a faint sheen of pork collagen.