In a small bowl, combine the coconut and boiling water. Set aside to soak.

Stir the tamarind and the water it has been soaking in. Using your fingers, remove the tamarind flesh and squeeze the juice from the pods, removing any fibers and membranes as well. Pour the mixture into a fine-mesh strainer set over a bowl and use a spoon to press as much of the pulp as possible through the strainer. Set the tamarind pulp aside.

In a skillet over medium heat, heat 2 tablespoons of coconut oil.

Add the mustard seeds and cook until they begin to sputter, about 1 minute.

Add the coriander seeds, fennel seeds, cumin seeds, peppercorns, and fenugreek. Sauté until fragrant, about 30 seconds.

Add the Guntur chiles to the skillet and stir-fry for 3 to 4 minutes, until they are slightly browned.

Drain any remaining water from the coconut and add it to the skillet along with the garlic and chopped onion. Cook for 5 to 6 minutes, until the onion is softened. Transfer the mixture to a bowl and set aside to cool. Once cool, transfer to a blender or food processor, add 1⁄2 cup of water, and process until a smooth paste forms.

In a wide pot over medium heat, heat the remaining 2 tablespoons of coconut oil.

Add the curry leaves and fry briefly.

Add the red onion and turmeric and cook for 5 to 7 minutes, until the onion is browned.

Add the chicken. Cook for 3 to 4 minutes, until golden and nearly cooked through, stirring continuously.

Add the tomatoes and cook for 1 to 2 minutes, stirring frequently.

Add the onion-spice paste and stir well to mix. Use the remaining 1⁄4 cup of water to rinse out the blender jar and add this to the pot as well.

Stir in the tamarind pulp and coconut milk and bring the curry to a simmer. Remove the pot from the heat and season with the salt.