Preview unusual treats (6)
I believe the answer is:
taster
'preview' is the definition.
(a taster is a preview or sneak peek)
'unusual treats' is the wordplay.
'unusual' is an anagram indicator.
'treats' is an anagram of 'TASTER'.
(Other definitions for taster that I've seen before include "One trying" , "Winery worker" , "Sampler of food" , "Sample intended to stimulate interest" , "Art set (anag.)" .)