Boil the potatoes and dice them. Chop the onions, garlic, ginger, coriander.
Heat oil and saute the cumin seeds until they crackle.
Add the onion, garlic and ginger and saute until golden.
Stir in the chopped ginger and add the potatoes.
Sprinkle turmeric, garam masala, coriander powder and chilli powder. Toss.