When Mughol come to bengali subcontinent, they want to whole power of bengal and this continent. Mughol was eat verious kind of fatty food and they also ate biriyani. After they came to bengal area, first biriyani was made in dhilli capital of india now. Then it spreade in whole bengal. After that time, Now this area's people love biriyani and it's a traditional food in this area.