Candlenuts
Aleurites moluccanus, Kukui Nuts or Indian Walnuts
Candlenuts are the kernels of the evergreen candlenut tree (Aleurites moluccanus), which thrives in China, India, Southeast Asia and on the Pacific islands. The kernels contain a lot of oil and are used as a spice in many Southeast Asian cuisines.
They taste slightly sweet and nutty, reminiscent of almond, but they also carry a note of nutmeg. Often they serve as a flavour enhancer. You should only use them roasted, because roasting removes toxins that would otherwise cause stomach cramps and nausea.
Other names for the kernels are “Kukui Nuts”, “Indian Walnuts” and “Lightnuts”. The name candlenut goes back to the fact that candles can be made from their oil. In German they are known as “Kemirinüsse”, “Lichtnüsse” or “Kerzennüsse”.
Macadamia nuts are often named as a substitute for candlenuts. To my taste they lack the note of nutmeg. You can possibly replace them with a mixture of macadamia nuts and mace.