- Take a pressure cooker and add potato,water and cook for 2-3 whistles. Then take a pan and add oil, mustard, cumin and saute. Then add onion. Add chopped tomato and cook for 4-5 minutes. Then add boiled and cubed potato and mix well. And add water. Add salt,red chilli powder,green chilli paste, Turmeric corinader powder,cumin powder and mix well turn off the flame garnish with coriander and serve hot.