Boil the potatoes and cut into two halves or leave as such if they are really small. Prick them with a fork and set aside.
Heat a nonstick pan, dry roast the spices to be grounded and blend in a food processor.
Add half of this grounded masala in beaten curd and add dried ginger powder. Whisk this curd again and set aside.
Heat oil in an open mouthed wok. Fry the potatoes from both sides till golden and drain on paper towel.
Remove all the oil from wok leaving around 4 tablespoon in it. Add asefetida , dried fenugreek leaves ,sauté for 1 minute.
Now add Kashmiri mirch powder from side of wok keeping it on low heat add tomato purée and green chilly paste. Sauté for 5 minutes.
Add the curd we prepared and stir it for 2 minutes . Now add the remaining grounded masala , coriander powder , salt and garam masala. Add 4 cups of water . Cook for 5-7 minute.
Let it boil. Add the fried potatoes and let it cook for 10 minutes on low heat (slow or dum cooking) till all spices get absorbed in potatoes and a nice gravy is formed.
Remove from heat , add chopped coriander and clarified butter.
Serve hot with chapati or Poori.
Notes
You may adjust water as per the consistency you want for the gravy.
Add chillies as per your taste.
Do not use too sour yougurt ot else the gravy will be way too tangy.