My grandmother used to have an epic passion fruit vine, fat with fruit. We'd collect the pockmarked nubs and shake them to see if they were ripe. The trick with passionfruit is that the uglier it is, the better it tastes. Interest in unusual fruits, especially tropical fruits, has been steadily rising for Passion fruit: An egg-shaped tropical fruit that is also called a purple . bred by crossing a grapefruit with an orange or tangerine, is indeed ugly.