Clean mushroom as shown in the link, slice it and keep aside.
Dry roast coriander seeds and red chillies for few mins until nice aroma comes. Cool down, transfer to mixer and grind it to a slightly coarse powder, set aside.
Heat oil, add onions, ginger garlic paste and saute till onions turn slightly browned.
Next add the spice powder and saute for a minute.
In a mixer add tomatoes and grind to a fine paste and add it along with onions.
Saute till raw smell leaves, then add little water and let it boil.
Add garam masala powder. While it boils in another pan add little oil, toast capsicum and onion for 2mins, Set aside.
Then add mushroom and saute for 2mins.
Then add mushrooms and cook till it turns soft. Then add fresh cream and let the gravy boil.
When the gravy starts giving a nice aroma, and the consistency is semi thick add toasted onion capsicum and give a quick stir.
Finally garnish with corainder leaves,kasoori methi and switch off.
Serve Kadai Mushroom with veg pulao or plain steamed basmati rice.