Sweet pudding gone after seconds (4)
I believe the answer is:
sago
'sweet pudding' is the definition.
'gone after seconds' is the wordplay.
'gone' becomes 'ago' (I've seen this in other clues**).
'after' is a charade indicator (letters next to each other).
'seconds' becomes 's'.
'ago' after 's' is 'SAGO'.
(Other definitions for sago that I've seen before include "dessert?" , "Starchy food as white pudding" , "Starchy grain used in desserts" , "Edible powdery starch" , "Powdery starch used in cooking" .)