Kluwek

Pangium edule (Java, pakem; West Java, pacung, etcetera; Sumatra, kapayang). This is a large tree which produces almost nothing that is of any use to anybody except for its large, handsome seeds. These can be processed to give a good cooking-oil, they can be eaten by themselves if they are carefully prepared, and they are among the ingredients of several fine dishes (e.g. Rawon), to which they give a distinctive flavour and a denser colour. Don’t be put off by Burkill’s notes on the poisonous nature of these seeds. By the time they reach market, either in the East or in Holland, they have been made completely safe, and I have used them in family cooking here in England many times without the slightest ill-effect. To prevent the poison (which is hydrocyanic acid) from forming, or to break it down after it has formed, we either boil the seeds several times, soaking them in running water in between, or, as my grandmother used to do in Sumatra, bury them for 10 or 15 minutes deep in the embers of a wood cooking-fire, where the seeds will become very hot but will not actually scorch. Then we crush and remove the shells and pound the seeds thoroughly in a large mortar. Note, by the way, that kluwek bought in Holland have been dried for the journey, and must be soaked for 30 minutes or boiled until soft before you start trying to grind them up. The inside of the nut is very dark red, frequently almost black.