In restaurants we demand some veg (5)
I believe the answer is:
swede
'veg' is the definition.
(swede is a kind of vegetable)
'in restaurants we demand' is the wordplay.
'in' says the answer is hidden in the clue.
'SWEDE' can be found hidden inside 'restaurants we demand'.
'some' is the link.
(Other definitions for swede that I've seen before include "North European" , "Someone from Gothenburg" , "Nobel for one" , "N European" , "Native of Stockholm" .)