The fruit of the pangium edule mangrove tree is poisonus. Yet, its the star of a Pernakan dish known as Ayam (Chicken) Buah Keluak as it is known in Indonesia. The poisonus nut is made edible by boiling and buried in ash for 40 days. The creamy colored nut turns black in the process. Hence, the need to soak in water and brush the outer coat for about 4 days.
Its an acquired taste, the way Chinese love fermented beancurd, durians and burning hot-pot. Or French like blue-cheese and Roquefort.