Steps
1. Heat oil in a pan over medium heat.
2. Add mustard seeds and cumin seeds; let them splutter.
3. Add chopped onions and sauté until golden brown.
4. Add chopped tomatoes and cook until soft.
5. Add turmeric, red chili powder, coriander powder, and salt; mix well.
6. Add diced potatoes and stir to coat with the spices.
7. Pour in water, cover, and cook on low heat for 15-20 minutes until potatoes are tender.
8. Check seasoning and adjust salt if needed.
9. Serve hot with rice or bread.