In a pan heat butter and add rice and saute it on slow flame and keep aside.
Seperately in another pan heat olive oil and saute onions and garlic and then add sliced mushrooms and little salt, pepper , oregano and chilli flakes.
Now mix the rice and sauté for a while and gradually add stock 1/2 cup and cook and then again 1/2 cup and so on till the rice is nicely done.
Once done, add basil leaves , lemon juice and parmesan cheese , mix and serve hot.