01 - Heat 2 tablespoons olive oil and 1 tablespoon butter in a large heavy-bottomed pan over medium heat. Add the onion and cook until translucent, about 3 minutes.
02 - Incorporate minced garlic and cook for 1 minute until fragrant.
03 - Stir in sliced mushrooms and cook 6 to 8 minutes until softened and liquids have evaporated. Season with salt and pepper.
04 - Add Arborio rice and stir for 2 minutes, allowing grains to lightly toast and become translucent at edges.
05 - Pour one ladle of warm vegetable broth into the rice. Stir constantly until most liquid is absorbed. Continue adding broth one ladle at a time, stirring frequently, allowing each addition to absorb fully. Cook 20 to 25 minutes until rice is creamy and al dente.
06 - Stir in remaining 2 tablespoons butter and grated Parmesan until melted and creamy.
07 - Remove from heat, drizzle with truffle oil, sprinkle with chopped parsley, and adjust seasoning as needed.
08 - Transfer to plates and garnish with additional Parmesan and parsley. Serve immediately.