Yunnan Suan Tang Yu

Suan tang yu — sour broth fish — is a dish beloved across Southwest China but finds one of its most aromatic forms in Yunnan, where it is flavoured with fermented tomatoes, wild sour herbs, and the region's distinctive dried chillies. The broth is a bright, golden-red soup with a clean acidity that comes from fermented ingredients rather than vinegar, which makes it refreshing rather than sharp. Whole freshwater fish, typically grass carp or tilapia, are simmered directly in the broth at the table.

Serves: 4

Ingredients

• 1 whole grass carp or tilapia (800 g–1 kg / 1.7–2.2 lb), cleaned and cut into thick steaks
• 3 tbsp (45 ml) neutral oil
• 200 g (7 oz) fermented tomatoes (or 4 ripe tomatoes, roughly chopped, plus 1 tbsp rice vinegar)
• 3 dried red chillies
• 4 slices fresh ginger
• 4 cloves garlic, smashed
• 2 stalks lemongrass, bruised
• 1.5 litres (6 cups) water or light fish stock
• 1 tsp (5 g) turmeric powder
• 2 spring onions, cut into lengths
• 1 handful fresh coriander
• 1 tbsp (15 ml) fish sauce
• Salt to taste
• Fresh chilli and lime wedges, for serving

Instructions

1. Heat oil in a large clay pot or heavy pot over medium heat. Fry the ginger, garlic, dried chillies, and lemongrass for 1 minute until fragrant.
2. Add the fermented tomatoes (or fresh tomatoes) and cook, crushing them with a spoon, for 5 minutes until they break down and release their liquid.
3. Pour in the water or fish stock. Add turmeric and bring to a boil.
4. Simmer uncovered for 15 minutes to develop the broth. Season with fish sauce and salt.
5. Add the fish steaks and cook over medium heat for 8–10 minutes until the fish is just cooked through — the flesh should flake easily from the bone and be opaque throughout.
6. Add the spring onions in the final 2 minutes.
7. Serve directly from the pot, topped with fresh coriander, sliced chilli, and lime wedges on the side.

Cook's Notes: Fermented tomatoes (sui qie zi) are available in Yunnan ingredient shops and some Asian grocers — they give an irreplaceable depth of sour flavour. If unavailable, the rice vinegar substitute works well. Do not overcook the fish; it will continue cooking in the hot broth at the table.