- Make a mixture of cumin powder, coriander powder, chili powder by using water. Heat oil in a pan, add mustard seeds, cumin seeds, let it splutter. Then add chopped onions, fry till they are slightly brown in color. Add turmeric and ginger garlic paste and mix it for about half a minute.. In the same pan, add chopped green chilies, prepared spices mixture, crushed fenugreek leaves . Fry on medium flame for 2 minutes. Then add boiled potatoes and saute . Once they are done, add chopped coriander leaves and simmer for 5 minutes more.