01 - Heat 2 tbsp butter in a large skillet over medium-high heat. Add the sliced mushrooms and sauté for 6–8 minutes until golden and tender. Season lightly with salt and pepper. Remove mushrooms from the pan and set aside.
02 - In a large saucepan, heat olive oil over medium heat. Add chopped onion and cook for 3–4 minutes until translucent. Add minced garlic and cook for 1 minute more.
03 - Stir in Arborio rice and cook, stirring constantly, for 2 minutes until the grains are lightly toasted and coated with oil.
04 - Pour in the white wine and cook, stirring, until it has mostly evaporated.
05 - Add warm vegetable broth, one ladle at a time, stirring frequently. Let the rice absorb most of the liquid before adding more broth. Continue this process for 18–20 minutes, until the rice is creamy and al dente.
06 - Stir in the sautéed mushrooms, Parmesan cheese, extra butter, and heavy cream (if using). Mix gently until well combined and creamy. Season with salt and pepper to taste.
07 - Remove from heat. Drizzle with truffle oil and stir gently.
08 - Serve immediately, garnished with chopped parsley and extra Parmesan if desired.