Take a Kadai and heat it on the medium flame. Then add marinated mushroom to the Kadai and boil it until the mushroom is cooked.
Then take a handi and heat it on the medium flame. Then add ghee at the bottom. Add a layer of boiled rice.
Add mushroom masala on the top of the rice and then add one more layer of boiled rice on the top of the mushroom masala.
Add shallots, ghee, chopped coriander or mint leaves on the rice. clean mushroom masala Kadai with milk and pour that milk on the top of the rice.
If you are using saffron, add that saffron to the milk and pour it on the rice. This giver extra color to the rice.
At last cover, the handi with lid and seal the edges with dough, so that pressure can't escape.
Can use silver foil to seal the plate. Should keep some weight on the plate so that the pressure cannot escape. Then cook it on the low flame for 15 to 20 mins.
Finally, serve the hot mushroom biryani with raita.