Caju by John Spottiswood.

This Brazilian fruit looks like a squishy apple with an odd-looking stem growing out of it. According to botanists, though, the grayish "stem" is actually the fruit, and it encloses the kidney-shaped cashew nut that we're familiar with. The cashew apple is the yellowish-orange part that's attached to the fruit. Cashew apples are juicy but somewhat astringent due to a high concentration of tannin. Be careful of the grayish fruit that encloses the nut. It contains toxic oils.