1.heat the oil and temper with asafoetida,fenugreek and cumin seeds.
2.add potatoes, turmeric powder and salt, and stir.
3.after 3 mins, add the ginger and garlic, and stir for 1 mins.
4.add the tomatoes, green chillies, spices and 2 cups of water. boil till the potatoes are cooked and tomatoes become soft .stir with a ladle, crushing the vegetables a little so that the gravy thickness.
5.put in the green coriander and cook for 2 more mins .serve hot.