Temper the oil with Hing, Green Chilies and Kalonji. Once it starts spluttering, add the potato cubes.
1/2 tsp Nigella Seeds/Kalo Jeera/Kalonji, 2 Green Chilies, 1/4 tsp Hing or Asafoetida, 2 Potatoes
Stir it once and season it with some salt as per your taste.
Salt to Taste
Add the water and put on the lid of the pressure cooker. Allow it to whistle for once and then turn off the heat and let the steam disperse on its own.
1/2 cup Water
Then open the cooker and check if the potatoes are done. Also, check the consistency of the gravy as per your need.