In a Dutch oven or large pot over high heat, cook potatoes in boiling water until just tender, 15 minutes, drain and set aside.
In same pot, heat oil over medium high heat. Cook mustard and cumin seeds until they pop, 1 minute. Add the asafoetida, fenugreek seeds and curry leaves and cook 1 minute. Next add the onion, garlic, ginger and chiles, cooking 3 minutes.
Add the potatoes, coriander, turmeric and salt. Reduce heat to low, toss to coat potatoes and cook, covered for 5 minutes.
Uncover and stir, mashing lightly with back of spoon. If there is still liquid, cook uncovered until slightly dry, another 1-2 minutes.