Star __: expensive spice (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
anise
(Other definitions for anise that I've seen before include "Aromatic Mediterranean plant" , "Herb with aromatic seeds" , "Plant with liquorice-flavoured seeds" , "Plant with aromatic seeds" , "Plant providing flavour similar to liquorice" .)