Macadamia

The macadamia is the round, cream-coloured kernel of an evergreen rainforest tree native to eastern Australia — the only Australian native plant grown anywhere as a major commercial food crop. Famous for its rich, buttery, faintly sweet flesh and the highest fat content of any common nut, it is locked inside one of the hardest shells in the plant world, which is why it long carried a reputation as the most expensive nut on the shelf.