1.8kg/4lb pork belly, skin off, cut into large cubes (ask your butcher to do this)
200ml/7fl oz white wine vinegar
5 tsp chilli powder (less if using hot chilli, a little more if mild)
3 tsp turmeric
2 tsp yellow mustard seeds
4 tsp cumin seeds
Sunflower oil, for frying
7 onions, 6 chopped and 1 sliced
8 garlic cloves, crushed
Thumb-sized knob of ginger, peeled and grated
Chutneys and naan bread, to serve
Put the meat in a large non-metallic bowl, then add the vinegar and spices. Mix well, cover and leave in the fridge for up to 24 hrs.
Heat 3 tbsp oil in a deep frying pan, then gently fry the chopped onion, garlic and ginger for 10 mins until softened. Tip in the meat and all of the marinade, season, then let the meat cook in its own juices for about 10 mins. It doesn’t need to brown. Pour in enough cold water to cover, then simmer for about 1½ hrs until the meat is very tender.
Meanwhile, heat 1cm oil in a frying pan until hot, then fry the sliced onion for about 4 mins or until crisp and golden. Drain on kitchen paper and set aside. Sprinkle the onions over the curry to serve.