Heat oil in a non-stick pan or a thick bottom pan. Crackle cumin seeds till they are light brown. Add asafoetida powder.
Add turmeric powder and green chillies.
Add potatoes, salt and combine everything. Cover and cook on very low heat till the potatoes are tender ( 90% cooked ). Stir in between to avoid scorching and over cooking. Add spring onions.
Also add tomatoes and chilli powder.
Combine everything well.
Cover and cook tilll the tomatoes and spring onions are tender and the potatoes are fully cooked. Cook without a lid for a minute or two or until the oil oozes.
Serve hot with roti/puri/paratha/rice or enjoy it as a single dish like salad.