Plump for dessert (4-4)
I believe the answer is:
roly-poly
This clue is a double definition.
'plump' is the first definition.
(I've seen this before)
'dessert' is the second definition.
(roly-poly is a kind of dessert)
'for' is the link.
(Other definitions for roly-poly that I've seen before include "Short and plump" , "Substantial" , "Plump and round" , "Podgy person -- pudding" , "Desert pudding of suet and jam" .)