The city provides you with all sorts of cuisine Chinese, Lebanese, Korean, Japanese, Thai, American and so on...
if you are willing to try Bengali cuisine go to the southern part of the city namely Tero Parbon, Saptapadi, ITC Royal Bengal etc.
Also Kolkata is known for its Biriyani. Try Kolkata Biriyani at Arsalan, Aminia, Kareems,Kabuliwala e.t.c