Polish potato dish mostly found in New York City (7)
I believe the answer is:
buffalo
'in new york city' is the definition.
(I've seen this before)
'polish potato dish mostly' is the wordplay.
'polish' becomes 'buff' (buffing is a kind of polishing).
'potato dish' becomes 'aloo' (I've seen this before).
'mostly' means to remove the last letter (most but not all of the word).
'aloo' with its final letter taken off is 'alo'.
'buff'+'alo'='BUFFALO'
'found' is the link.
(Other definitions for buffalo that I've seen before include "Zoo's inhabitant" , "Animal whose milk made mozzarella initially" , "Kind of cattle" , "Brown bison of North America" , "Herd animal; New York port" .)