Cold dessert (6)
I believe the answer is:
trifle
'cold dessert' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for trifle that I've seen before include "Dessert; act frivolously" , "Act foolishly" , "Small amount; dish" , "Type of dessert" , "Pudding - bagatelle" .)