Saint having something for breakfast, sandwiches run out (7)
I believe the answer is:
brendan
'saint' is the definition.
(I know that Brendan is a saint)
'something for breakfast sandwiches run out' is the wordplay.
'something for breakfast' becomes 'bran ' (I've seen this before).
'sandwiches' indicates putting letters inside (goes on either side like a sandwich).
'run out' becomes 'end' (synonyms).
'bran' enclosing 'end' is 'BRENDAN'.
'having' is the link.
(Other definitions for brendan that I've seen before include "Early Irish saint" , "- Behan, Irish dramatist" , "Chap" , "-- Behan, Irish author" .)