01 - Heat olive oil and 1 tablespoon unsalted butter in a large skillet over medium heat. Add sliced mushrooms and cook until golden brown and most moisture has evaporated, about 7 minutes. Remove half the mushrooms and set aside for garnish.
02 - Add chopped onion to the skillet and sauté until softened, about 3 to 4 minutes. Stir in minced garlic and cook for an additional minute.
03 - Add Arborio rice to the skillet and toast, stirring constantly, for 2 minutes until the grains are well coated and slightly translucent.
04 - Pour in dry white wine and cook, stirring frequently, 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 be absorbed before adding the next. Continue for 18 to 20 minutes until the rice is creamy and al dente. Not all broth may be needed.
06 - Reduce heat to low. Stir in reserved mushrooms, grated Parmesan, heavy cream, and remaining 2 tablespoons unsalted butter. Season with salt and freshly ground black pepper. Cook for 2 minutes until heated through and creamy.
07 - Plate immediately and garnish with fresh parsley and extra Parmesan cheese if desired.