Posh Spice dancing for fans (7)
I believe the answer is:
saffron
'posh spice' is the definition.
(saffron is an expensive spice)
'dancing for fans' is the wordplay.
'dancing' is an anagram indicator.
'for'+'fans'='forfans'
'forfans' anagrammed gives 'SAFFRON'.
(Other definitions for saffron that I've seen before include "Spice from crocuses" , "Valuable spice" , "The stigma" , "Fans for, say orange food flavour and colouring" , "Orange-yellow spice" .)