Heat oil in a pan.
Saute onions,mushrooms & garlic.
Add salt.
Mix in the pepper powder and sumac powder.
Move aside the filling in the same pan and add butter on the other side.
Add crushed ginger and saute.
Add the chicken if using and saute well.
Add the thick cream and mix until the mixture thickens.
Butter the baking dish.
Cut half the buns and place it in the dish.
Spread the mushroom filling .
Cover it with the other half Bun.
Sprinkle cheese.
Bake @180° until cheese melts.
Serve hot.
