Biryani is classified as any number of spiced South Asian rice dishes, heavily spiced, and layered with meat—often chicken, lamb, or beef. The biryani at Sangam, a new hole in the wall spot on Bleecker Street just east of 6th Avenue, receives what owner Ishrat Ansari calls “an authentic royal haute cuisine preparation.” The description is definitely merited when it comes to his wife Rafat’s homegrown recipe, which is served all vegetable, with chicken,......