Heat clarified butter in a pan, add dried methi, asefetida ,cumin seeds and ginger. Stir for a minute or two.
Add all of the spices and salt .Keep on low flame.
Now add chopped tomatoes and green chillies. Mix and cook till ghee comes out from edges.
Add mashed potatoes and few coriander leaves , toss well and press them gently with spatula. Pour 2 to 3 cups of water. Let it cook for 20 minutes until water mixed with potatoes and the oil or ghee comes out.
Add chopped coriander and 1/2 teaspoon clarified butter .Serve hot with Khasta Kachories ,Poori and Chapati .
Notes
You can prepare this curry in oil also but for best results try with clarified butter.If you don't want to add tomatoes just add a teaspoon of more dried mango powder.Always add spices and salt on as per your taste preferences.