Wearing gloves, slice the jackfruit into 8cm / 3 inches long by 4cm / 1 1/2 inches wide pieces and peel off the outer comb. Remove the seeds.
Heat the mustard oil in a large, heavy-based pan over medium heat, add the jackfruit and potatoes and fry for 15 minutes, or until they turn golden brown. Remove from the pan and set aside. You may need to do this in batches.
Heat the ghee or oil in another large, heavy-based pan over medium heat, add the asafoetida, cumin seeds, and fenugreek seeds, and stir-fry for about 1 minute, or until the seeds start to splutter.
Next, add the fried jackfruit and potatoes and all the remaining ingredients, except the chopped coriander.
Pour in 500ml / 18fl oz (2 1/4 cups) water, reduce the heat slightly and simmer for 15 minutes, shaking the pan frequently. When the jackfruit and potatoes are soft to the touch, add the chopped coriander.