Favour class beset by routine (7)
I believe the answer is:
rosette
'favour' is the definition.
('favour' historically meant a token of affection)
'class beset by routine' is the wordplay.
'class' becomes 'set' (I've seen this before).
'beset by' indicates putting letters inside ('beset' could historically mean 'cover').
'routine' becomes 'rote' (I have seen 'Mechanical routine ' mean 'rote' so perhaps 'routine' could also mean 'rote').
'set' inserted within 'rote' is 'ROSETTE'.
(Other definitions for rosette that I've seen before include "sign of support for party" , "Test ore (anag) - badge" , "Ribbon in a cluster as an award" , "collection of ribbons" , "Equestrian prize" .)