In a heavy bottomed sauce pan, add chopped onions, half the curry leaves, chillies and ginger.
Add all the powders, 3 tbsp of oil and salt and rub in with hand.
Add cut potatoes and rub the mixture in well.
Pour 3/4 cup of coconut milk over the mixture followed by water and keep on low flame.
Bring the mixture to boil and wait until the potatoes are fully cooked.
Once the potatoes are completely cooked, pour rest of the coconut milk and boil once on low flame.
Immediately, add the vinegar and turn off the heat.
Heat 2 tsp of oil in another pan.
Fry the finely chopped small onions and curry leaves until golden brown.
Pour the entire mixture over the potato curry.
:- Serve with Rice or Chappathis and any side dish.