Pound green chili, garlic, ginger into a coarse mixture
Heat oil in a pan
Temper mustard seeds and allow it to splutter
Add cumin seeds and allow it to splutter
Add the pounded mixture and sauté well
Add curry leaves and fry until crispy
Add turmeric powder, coriander powder, cumin powder, red chili powder, asafoetida, rock salt and mix well
Add potato and mix well with the above masala and cook until tender in low flame
Stir the potatoes occasionally so that every piece will cook evenly
Allow the potato to roast