Pangium edule
Pangium edule, or keluak, is neither a fruit nor a nut. In fact, it’s the seed of the keluak tree that is widely used in South Asian cuisine, although the seeds contain hydrogen cyanide. You can eat them only after they have been boiled without their shells and buried in ash and banana leaves for 40 days. Only after this complicated procedure do they become safe for eating, acquiring a special taste and flavor.