Upper-class boy tucking into eggs and Swiss roll, for example (7)
I believe the answer is:
roulade
'swiss roll for example' is the definition.
(type of roulade)
'upper-class boy tucking into eggs' is the wordplay.
'upper-class' becomes 'u' (similar in meaning).
'boy' becomes 'lad' (informal term for boy).
'tucking into' indicates putting letters inside.
'eggs' becomes 'roe' (I've seen this in another clue).
'u'+'lad'='ulad'
'ulad' inserted within 'roe' is 'ROULADE'.
'and' is the link.
(Other definitions for roulade that I've seen before include "run" , "part of a song" , "Melodic embellishment" , "Food that's filled" , "passage not easy to negotiate" .)