Peel & wash potatoes. Chop them into bite size pieces.
Coarsely grind chopped tomatoes into a paste. Set aside.
Break the wadi into small pieces. Do not grind it, just use your hands to coarsely break it.
Heat 1 tsp ghee in a cooker and roast the wadi pieces till golden brown. Remove into a bowl and set aside.
In the same cooker, now heat the remaining ghee. Firstly add asafetida, then allow cumin seeds to pop.
Now add ginger, and green chilies, cooking for another minute until aromatic. Mix in remaining spices like turmeric powder, coriander powder, red chili powder, and tomato puree. Cook for 2-3 minutes till tomato puree starts leaving ghee/ oil.
Now add both potatoes and roasted wadi to the prepared masala. Add 1 cup water and salt as per taste.
Pressure cook for 2 whistles on low flame till potatoes are tender and subzi absorbs the flavors of the curry.
Sprinkle garam masala and amchur for a tangy kick. Adjust the salt as needed. Garnish with fresh coriander leaves before serving.