Mangosteens are a tropical fruit native to Southeast Asia and the Malay archipelago. They are difficult to grow outside of their native habitat. They are also found in freeze-dried form at Trader Joe's and canned in Asian supermarkets. Personally, we shun the dried and canned and hold out for the fresh fruit.
Fresh mangosteens will likely be found in Asian markets for a while before they hit mainstream supermarkets. They can also be found online at Frieda's, but be prepared to empty your wallet.
Pick fruits that have firm outer rind. They are very easy to open; simply score the outer rind with a serrated knife along the "equator," taking care not to slice through to the pulp. Twist off one section and presto - the delicacies beneath are now present to you. Pick off a section and pop it in your mouth, and enjoy! Oh - and take care not to let any juice from the purple rind stain your clothes or fingers; it's difficult to wash off.
Happy exotic fruit hunting!
(Images: Kathryn Hill)