Cassava product (7)
I believe the answer is:
tapioca
'cassava product' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tapioca that I've seen before include "Cassava product used for puddings" , "Pudding made from an extract of cassava" , "it thickens" , "Starchy pudding" , "Foodstuff used as a thickener" .)