City diner mostly cooked hot food from the east (9)
I believe the answer is:
edinburgh
'city' is the definition.
(Edinburgh is an example)
'diner mostly cooked hot food from the east' is the wordplay.
'mostly' means to remove the last letter.
'cooked' indicates anagramming the letters.
'hot' becomes 'h' (abbreviation eg on taps).
'food' becomes 'grub' (grub is a kind of food).
'from the east' says the letters should be written in reverse.
'h'+'grub'='hgrub'
'hgrub' backwards is 'burgh'.
'diner' with its last letter taken away is 'dine'.
'dine' is an anagram of 'edin'.
'edin'+'burgh'='EDINBURGH'
(Other definitions for edinburgh that I've seen before include "City on the Firth of Forth" , "fringe city" , "Scotland's capital" , "Auld Reekie" , "'The Athens of the North'" .)