Feijoas, also known as Pineapple Guavas, are the fruit of an evergreen myrtle-family plant, native to the highlands of many South American countries. The fruit matures in autumn and has an incredibly aromatic, almost tropical flavor, with a juicy, if sometimes a bit grainy, pear-like texture.
Wait for Feijoa's skin to turn from a dark green to a somewhat yellower green and for the fruit to give gently to the touch to eat. You can eat the skin as well as the flesh, though some people prefer to avoid the skin, as it is much tarter than the flesh alone.