01 - Heat olive oil and 1 tbsp butter in a large skillet or saucepan over medium heat. Add the mushrooms and sauté until golden brown and most moisture evaporates, about 7 minutes. Remove half the mushrooms and set aside for garnish.
02 - Add the onion to the skillet and cook until softened, 3 to 4 minutes. Stir in the garlic and cook for 1 additional minute.
03 - Add the Arborio rice and stir continuously for 2 minutes until grains are well-coated and slightly translucent.
04 - Pour in the white wine and cook, stirring, until the liquid is fully absorbed.
05 - Begin adding warm vegetable broth one ladleful (about ½ cup) at a time, stirring frequently. Allow each addition to absorb before adding the next. Continue until rice is creamy and al dente, approximately 18 to 20 minutes. All broth may not be needed.
06 - Reduce heat to low. Stir in reserved mushrooms, Parmesan, heavy cream, and 2 tbsp butter. Season with salt and pepper to taste. Cook for 2 more minutes until creamy and heated through.
07 - Serve immediately, garnished with fresh parsley and additional Parmesan if desired.