Pressure cook the potatoes for a whistle on high flame and switch off. Allow the pressure to go on its own. Peel and cube them. The potatoes should be cooked yet firm.
Heat oil in a saucepan, splutter the cumin seeds.
Add the capsicum and saute till slightly wilted and charred.
Add in the potatoes and the remaining ingredients except coriander leaves and give it a good toss. Add 1/2 cup of water and bring it to boil.
Cook on simmer for five minutes or till gravy thickens.
Serve hot, garnished with coriander leaves.