Stefanie Wairisal of the Mutiara Hotel in Ambon cooked this for me using long, thin, purple aubergines, which have a soft skin. You may be able to get these, or white aubergines; if these are not available, use the large, fat, purple ones, but cut them lengthwise into quarters instead of halves.
Farther east, in the Banda Islands, the sauce is often made with kenari nuts instead of coconut milk. The kenari must be blanched first. If you are making this in the West, I suggest you use