For preparing the Ishtu or the delicious potato stew, first grind coconut with water and strain it to get thick coconut milk (Onnam paal).
Grind it again with water and strain to get slightly thinner coconut milk (Randaam paal).
Dice potatoes and onions and cut the carrot and green chillies lengthwise.
Cut ginger into long strips.
Boil all the vegetables with salt and little water. Drain off the excess water after the potatoes are done.
Pour in the second coconut milk and allow it to boil.
When it boils, add the thick coconut milk and reduce the flame.
When it starts bubbling, take the vessel off the fire.
:- Do not boil, as it will curdle.
Add butter/ coconut oil and curry leaves.
:- Serve hot with idli, dosas, vellayappam or even bread.