Wash and clean the mushroom thoroughly. Slice them accordingly.
Slice the onions, garlic and capsicum.
In a pan heat 2 tablespoons oil and fry the garlic cloves for a minute. Then add the onions and saute until the onions become translucent.
Then add capsicum and fry for a minute.
Now add the mushroom and mix well. Add in the required salt (about 1 3/4 tablespoons). And add in the garam masala powder too.
Give it a good mix. Do not add water as mushroom will leave a lot of water.
Let it cook, stir occasionally. When the mushroom is half done (when some water has evaporated) add in a tablespoon of pepper powder.
You can add more or less pepper according to your need.
Keep stirring and cook until all of the water evaporated and oil leaves the sides.
Check for salt and add if needed.
Serve hot by garnishing with some coriander leaves.