Marinate duck with ingredients from 2 to 8 and transfer to a pressure cooker, leave to marinate for 30 minutes.
Now, place the whole potato on top of the marinated meat in pressure cooker. Let the pressure built up, after the first whistle, reduce heat and simmer for 10 minutes. Turn off the heat and let the steam release by itself. This takes about 10 minutes.
Heat oil in a large wok; sauté thinly sliced onion and small onion till soft; now add thinly sliced green chilli, ginger and garlic and saute for another minute or so.Stir in a tsp of garam masala and mix well.
Add cooked duck meat to this masala, add 1/4 cup of water. Remove the cooked whole potato from the pressure cooker, peel off the skin, gently cut the potato into wedges and add to the meat .
Add1/2 cup medium consistency coconut milk and mix well to combine ; to this pour about 1 cup water and bring to a boil. Add curry leaves and 1 tsp garam masala and let it simmer for another 20-30 minutes, in low heat or until the gravy thickens and oil clears on top.