I am from kolkata and I have been staying in guwahati since 2000. I love food but in kolkata is a very cheap and destination of very tasty food even from the street vendor. but in guwahati except momos I dont think so there was any good fast food shop that make good rolls biryanis etc at an affordable or high rate. never been satisfied with the food. they used to serve polaw calling them biryani . paratha by just frying the roti.
In 2014 or 15 if I remeber the shop bade miyan opened near my locality and the cook was from kolkata very good chicken roll and biryani.you can call it laajawab. but in 2016 they replaced the cook everything went wrong and was closed recently.