Dry roast the coriander seeds in a heavy bottom skillet till aromatic. It usually takes 1 - 2 minutes. Transfer them to a mortar and crush to a coarse powder using a pestle. Set aside.
Next, heat mustard oil in the same skillet till it starts fuming. Reduce the heat to medium.
Add mustard seeds, cumin seeds, dry red chilies and fry till seeds start spluttering.
Add lentils, curry leaves, and asafoetida. Fry the tempering for next 2 - 3 minutes.
Now, add the baby potatoes, salt, spices, and coriander powder. Mix nicely to evenly coat each potato with the masala.
Cover and cook over low heat till potatoes are crisp from outside and fully cooked from inside. Stir the potatoes once or twice during this process.
Garnish with fresh curry leaves.
Serve Potato Fry with rasam and rice for a delicious South Indian style lunch.