To prepare the mushrooms, clean the mushrooms by brushing them off (do not wash if possible) and cut into quarters (stems may be left on).
In a medium sauté pan, melt the 1 tablespoon each of butter and olive oil. Add the cleaned and quartered mushrooms and sauté over medium-high heat until lightly browned, stirring frequently. (Note – it’s important to sauté the mushrooms over somewhat high heat in order to get the mushrooms to release their moisture without steaming the mushrooms.) Once the mushrooms are lightly browned and tender and plump, sprinkle lightly with just a touch of salt and allow to sauté for another minute more – this step will release just a bit more of the moisture in the mushrooms. Remove the mushrooms from the heat and set aside.
To prepare the rice, in a medium heavy-bottomed saucepan, melt the butter and olive oil together over medium-high heat. Add the diced onion and sauté for 5 minutes, until the onions are translucent.
Add the Arborio rice, stirring frequently for 2-3 minutes until the rice is just starting to turn lightly golden.
Quickly pour in the white wine and allow the liquid to boil and be absorbed into the rice. Then pour in ¼ cup of chicken stock to the rice, stirring constantly. (If necessary, adjust the heat under the pot – you want a medium simmer.) Add more stock ¼ cup at a time – adding more just as most but not all of the liquid is absorbed before adding in more stock.)
Cook the rice and stock together in this manner for approximately 25 minutes or so – until the rice is tender but not mushy. Turn the heat off when there is still some liquid remaining in the rice and stir in the parmesan cheese and mushrooms and salt and pepper to taste. Stir to combine completely.
Remove from heat and cover – let sit for 5 minutes before serving.
Note: Risotto may be reheated by adding in some additional chicken stock and stirring to incorporate into the risotto.