Break the aloo (potatoes), by holding each in the palm of your hand and closing the fist. Keep these unevenly broken potatoes aside until further use.
Heat the ghee, add cumin and asafoetida. When the cumin splutters, add ginger and sauté till slightly fried.
Lower the flame, add yogurt 1 tbsp at a time, stirring vigorously until all of it is well blended.
Add garam masala, coriander, salt, turmeric and chilli powder. Stir a few times until well mixed, add potatoes and green chillies, turn around over high heat, until they look slightly fried.
Add about 2 cups water, bring the mixture to a boil, and then simmer uncovered for about 15 minutes.
Serve aloo dahi wale hot, garnished with coriander leaves.