In Old Dhaka's kacchi method, raw marinated meat and raw rice go into the pot together and get sealed shut with dough — nothing is pre-cooked, so the rice finishes by steaming in the meat's own juices.
Mutton or beef marinated in yogurt and spices is layered with basmati rice and potato, then sealed in a heavy pot and slow-cooked so the raw meat and rice steam together. Old Dhaka's biryani houses around Nazira Bazar and Bakshibazar have served it as a wedding and celebration centerpiece for generations.