Saute garlic and cumin in oil until they begin to smell good.
Add tomatoes or puree, salt and turmeric. Cook until the tomato mixture turns thick and soft.
Saute capsicum, chilies and onions on a medium high flame until the raw smell of onions is gone. If you like to keep the onions and capsicum crunchy, skip now and add after the mushrooms are half done.
Saute mushrooms for 2 to 3 mins.
Add crushed pepper saunf and curry leaves. Fry for 2 to 3 mins.
Cover and cook on a low heat until the mushrooms are done.