In a pressure cooker or a vessel, add all the vegetable ingredients, salt, curry leaves, pour 1/2 cup coconut milk and cook the vegetables. If in a pressure cooker, just 1 or 2 whistles are required. The coconut milk will curdle and thats alright.
Once cooked, add the remaining 1 cup coconut milk.
Mash some of the potato so that the gravy gets thicker.
Warm it again. Make sure you remove from the stove much before it reaches boiling point.