Is youngster allowed in works restaurant? (7)
I believe the answer is:
canteen
'works restaurant?' is the definition.
(I've seen this before)
'is youngster allowed' is the wordplay.
I cannot really see how this works, but
'youngster' could be 'teen' (I've seen this before) and 'teen' is found within the answer.
The remaining letters 'can' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'in' is the link.
(Other definitions for canteen that I've seen before include "Flask - restaurant attached to institution" , "Cafe, flask and cutlery box" , "Workers' cafe and cutlery box" , "Water or cutlery container" , "Drinks flask" .)