Wobbly dessert (5)
I believe the answer is:
jelly
'wobbly dessert' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for jelly that I've seen before include "Wobbly food" , "Fruity dessert" , "Aspic" , "Gelatinous pudding" , "Wobbly stuff" .)