01 - Heat olive oil and 1 tablespoon butter in a large skillet over medium heat. Add onions and cook for 3 to 4 minutes until translucent. Stir in garlic and cook for 1 minute.
02 - Add sliced mushrooms, lightly season with salt and pepper, and cook until softened and golden, about 6 to 8 minutes. Transfer half the mushrooms to a bowl for garnish.
03 - Add Arborio rice to the skillet and toast, stirring constantly, for 1 to 2 minutes until the edges become translucent.
04 - Pour in white wine and stir until fully absorbed by the rice.
05 - Add warm vegetable broth one ladleful at a time, stirring frequently and allowing each addition to be absorbed before adding the next. Continue this process for 18 to 22 minutes until the rice is creamy and al dente.
06 - Stir in remaining butter, Parmesan cheese, heavy cream, and chopped parsley. Season with salt and black pepper to taste.
07 - Remove from heat, drizzle with truffle oil, and gently fold to combine.
08 - Plate immediately, topped with reserved mushrooms, additional Parmesan, and a sprinkle of fresh parsley.