2 sprigs fresh curry leaves, leaves picked, plus extra sprigs to serve
1 onion, thinly sliced
3 garlic cloves, crushed
1½ tsp ground turmeric
½ tbs tomato paste
400ml coconut milk
300ml fish or vegetable stock
1½ tbs tamarind puree
600g skinless chunky fish fillets (such as blue eye or ling), cut into 5cm pieces
150g cherry tomatoes, halved
¼ bunch coriander, leaves picked
Steamed brown basmati rice and lime wedges, to serve
Heat coconut oil in a large heavy-based saucepan over a medium-low heat, add dried chillies and mustard and coriander seeds, and cook for 1-2 minutes until fragrant and seeds start to pop. Add curry leaves, onion and garlic, then increase heat to medium and cook, stirring occasionally, for 5 minutes or until onions are soft.
Add turmeric and tomato paste and cook, stirring, for a further 2 minutes. Stir in coconut milk and stock, and bring to a simmer. Cook for 5 minutes or until sauce has thickened slightly and flavours have developed. Stir through tamarind, then add fish and simmer for 5 minutes or until fish is just cooked through. Stir through cherry tomato and coriander leaves (reserving a few sprigs to serve) to combine.
To serve, divide rice among serving bowls, spoon over curry, scatter with remaining curry leaves and reserved coriander sprigs, and serve with lime wedges.