Pudding to leave, after consuming seconds (7)
I believe the answer is:
dessert
'pudding' is the definition.
(thesaurus)
'leave after consuming seconds' is the wordplay.
'leave' becomes 'desert' (deserting is a kind of leaving).
'after consuming' indicates putting letters inside.
'seconds' becomes 's'.
'desert' going around 's' is 'DESSERT'.
'to' acts as a link.
(Other definitions for dessert that I've seen before include "End of meal" , "Charlotte maybe" , "Fruit and nuts, perhaps" , "Spotted Dick is one" , "Sweet, afters" .)