Heat the oil in a large, deep frying pan or flameproof casserole dish over medium heat and fry the shallots until translucent, about 3-4 mins. Add the garlic, ginger and chilli, and fry for another 2-3 mins until fragrant and lightly browned.

Stir in the curry powder and turmeric. Cook for about 1 min, stirring continuously to prevent the spices from burning. Add the tomato and cook until softened, about 2-3 mins.

Pour in the coconut milk and 200ml water, stirring to combine. Add the tamarind paste, lemongrass and lime leaves, and bring to a simmer. Add the aubergine and okra, and continue to simmer for about 20 mins until the vegetables are tender, adding a splash of water if the curry sauce has reduced.

Reduce the heat and gently lower in the fish pieces. Cover and simmer for 5-10 mins, or until the fish is cooked through and flakes easily when gently pressed with a fork. Season with salt to taste. Remove the lemongrass stalks and lime leaves, then garnish with the coriander and serve hot with steamed rice.