Drop round for pudding (4)
I believe the answer is:
sago
'pudding' is the definition.
(I've seen this before)
'drop round' is the wordplay.
'drop' becomes 'sag' (sagging is a kind of dropping**).
'round' becomes 'o' (round can mean a round object).
'sag'+'o'='SAGO'
'for' is the link.
(Other definitions for sago that I've seen before include "Edible powdery starch" , "Starchy cereal used in puddings" , "Edible palm starch" , "Type of milk pudding" , "Starchy foodstuff" .)