Ate some shortbread in Edinburgh (5)
I believe the answer is:
dined
'ate' is the definition.
(dining is a kind of eating)
'some shortbread in edinburgh' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'DINED' can be found hidden inside 'shortbread in edinburgh'.
(Other definitions for dined that I've seen before include "Ate a meal" , "Had supper" .)