Drank at spread, producing beer mug (7)
I believe the answer is:
tankard
'beer mug' is the definition.
(I've seen this before)
'drank at spread' is the wordplay.
'spread' indicates an anagram.
'drank'+'at'='drankat'
'drankat' with letters rearranged gives 'TANKARD'.
'producing' is the link.
(Other definitions for tankard that I've seen before include "A drinking mug with handle" , "Beer-glass" , "Drinking vessel with a handle" , "Beer-mug" , "One-handled drinking mug" .)