70 mlvegetable oil1onion, thinly sliced30 gmginger, finely grated3garlic cloves, finely chopped2star anise2vine-ripened tomatoes, coarsely chopped400 mlcoconut cream200 mlfish stock or chicken stock2long green chillies, split lengthways2 tbspwhite vinegar1 tbspcaster sugar500 gmfirm white skinless fish fillets, such as blue-eye trevalla, cut into 4cm pieces 12uncooked prawns, cleaned, tails intact8fresh curry leaves1 tspbrown mustard seedsTo serve:steamed jasmine rice and coriander sprigsSpice mix 6small dried red chillies1 tbspground coriander2 tspground cumin½ tspground cloves
For spice mix, dry-roast ingredients in a small frying pan until fragrant (1 minute). Transfer chillies to a mortar and pestle and finely crush, return to ground spices and set aside.
Heat 2 tbsp oil in a large saucepan over medium heat, add onion and stir occasionally until just tender (2-3 minutes). Add ginger, garlic, star anise and spice mix and stir occasionally until fragrant (1 minute). Add tomato, stir occasionally until liquid evaporates (1-2 minutes), add coconut cream, stock and chilli, season to taste with sea salt and simmer to develop flavours (8-10 minutes). Add vinegar and sugar, then fish and prawns and simmer gently until just cooked through (2-3 minutes).
While fish cooks, heat remaining oil in a small saucepan over medium-high heat, add curry leaves and mustard seeds, stir until fragrant and beginning to pop (30 seconds), then add to curry.