Remove the skin of arbi (kochu) and wash it. Then boil this till it’s soft. Discard the water. You could boil and remove the skin too. It’s a personal choice.
Heat mustard oil in a kadai, and add the whole spices one by one. Then add onions finely sliced.
Fry the onions on high heat for 3-4 minutes and then add garlic paste and ginger paste. Continue frying this on medium heat
Then make a mixture of half tsp of turmeric powder, Kashmiri red chili powder, coriander powder and cumin powder. Add water and add this to the onions.
Fry this masala for 3-4 minutes and then add a dollop of tamarind pulp.
Add the boiled kochu to this and mix everything. Fry on high heat for a couple of minutes and sprinkle salt and add half a cup of water.
Cover and let this soak in the liquid for some time over low heat. Then uncover and add sugar to balance the sourness of the tamarind, add split green chillies and that’s it.
Mix all this, if you feel a little more water is needed for the saucy consistency, do so and take it off the heat.