Lightly oil the knife to help with sticky sap. Remove the tough outer skin and central core completely, then cut the usable raw jackfruit into chunky strips.
Dry-roast the coriander seeds, cumin seeds, fenugreek seeds and Byadgi chillies for a few minutes, without burning them. Let them cool.
Grind the roasted spices with tamarind and turmeric, using a little water if needed. Add the grated coconut last and pulse for only a few seconds so the paste stays coarse.
Set the masala aside. Rinse the mixer with water and use this masala water to boil the jackfruit until tender, adding more water as needed. Drain the cooked jackfruit.
Heat 4 teaspoons coconut oil in a pan. Add mustard seeds, urad dal and curry leaves. Let the mustard splutter and the urad dal turn golden.
Add the coarse paste and cook, stirring, until it thickens and is on the drier side.
Stir in the drained jackfruit and salt. Mix well to coat the pieces with coconut masala and serve as a side dish.