First, run the mushrooms in clean water and let it sit in warm water for 2 minutes and not more. Meanwhile, you can chop onions, garlic and coriander keep them aside.
Now remove the water from the mushrooms and keep it aside.
Keep finely chopped onions, garlic, and coriander ready.
Heat butter and olive oil in a pan, once little hot, add onions in it.
Saute onions for 2 minutes till they are brown.
Now add mushrooms in it and saute it on a medium flame, stirring occasionally.
Mushrooms will take 5-6 minutes to cook and turn brown and crispy over the edges.
At this stage add minced garlic, salt, pepper powder, seasoning, and chili flakes.
Mix everything well and let it cook for another 2 minutes till mushrooms are tender and well cooked.
Finally, add finely chopped coriander leaves, stir it once and remove it in a bowl to serve.