Thinly slice the mushrooms and onion.
Add olive oil to a pan and sauté the onions.
When the onions become translucent, add the mushrooms and cook together.
Add the rice and stir-fry them together.
Pour in the white wine and let it reduce.
Gradually add warm broth and cook the rice.
Season with salt and pepper.
Turn off the heat and mix in Parmesan cheese and butter.
Serve on a plate and sprinkle with parsley to finish.