Boil potatoes either whole or chopped until fork tender. Drain, cool slightly, then peel and chop them. Set aside.
In a small bowl, combine turmeric, red chili powder, coriander, cumin, cinnamon and salt. Mix well and keep ready.
Heat oil in a large nonstick pan on medium heat. Add the mustard and cumin seeds and cook for 1~2 minutes or until the seeds start to splutter. Add the curry leaves, onions and cook for 3~4 minutes or until onions turn translucent.
Stir in the potato pieces and cook until they are crispy and browned, stirring occasionally, about 6~8 minutes. Add spice powder. Cook for 1~2 minutes, stirring constantly. Turn off the heat and serve hot with rice & dal!!