How to Make It
In a very large, deep skillet, heat the oil. Add the curry leaves and cook over moderately low heat until fragrant, about 2 minutes. Add the garlic and cook until softened, about 3 minutes. Add the shallots, ginger and chiles and cook for 5 minutes. Add the coriander, turmeric and cayenne and cook, stirring, until fragrant, about 2 minutes. Add the tamarind and tomato purees and simmer over low heat until thickened, about 10 minutes.
Season the tilapia fillets with salt and black pepper and nestle them in the sauce. Cover and simmer over moderately low heat, turning once, until the fish is just cooked through, about 4 minutes per side. Transfer the fish to plates and spoon the sauce on top. Garnish with the cilantro leaves and serve.