Cook learns nothing in Italian city (7)
I believe the answer is:
salerno
'italian city' is the definition.
(I've seen this before)
'cook learns nothing' is the wordplay.
'cook' indicates anagramming the letters.
'nothing' becomes 'o' (looks like zero - 0).
'learns' is an anagram of 'salern'.
'salern'+'o'='SALERNO'
'in' acts as a link.
(Other definitions for salerno that I've seen before include "City of Campania" , "Italian city; Orleans (anag.)" , "European city!" , "Learn so as to go out to the Italian port city" , "Orleans (anag) - Italian port" .)