Cake served during breakfast or tea (5)
I believe the answer is:
torte
'cake' is the definition.
(torte is a kind of cake)
'during breakfast or tea' is the wordplay.
'during' indicates the answer is hidden within the clue.
'TORTE' is hidden within 'breakfast or tea'.
'served' is the link.
(Other definitions for torte that I've seen before include "Rich sweet cake" , "German cream cake" , "Sweet cake or tart" , "Rich food" , "(Austrian) cake with cream and fruit or nuts" .)