Peel the koorka/Chinese potato and wash it well. pressure cook with salt, turmeric powder and chilly powder to 2- 3 whistles.
To saute and grind: Heat oil, drop in cumin seeds, coriander seeds, peppercorns,cinnamon, clove, shallots, green chilly and coconut. if using grated coconut add it at last after shallots turn brown.
Once coconut pieces turn slightly brown, switch off and add curry masal powder. This can be replaced with sambar powder or just chilly powder. But taste will differ. Cool and grind to fine paste.
Heat oil, splutter mustard seeds, crackle cumin seeds. saute chopped onions and chopped ginger until onions are brown. Add chopped tomatoes and saute until mushy. Curry leaves are also added along and sauteed.
Pour the ground masala and cooked vegetable (along with water used for cooking it). Add salt, pepper powder and curry masal powder to adjust to your spice level. Add water and pressure cook to 1-2 whistles.