01 - Heat olive oil and 1 tbsp butter in a large, heavy-bottomed skillet over medium heat. Add chopped onion and cook until soft and translucent, about 3 minutes.
02 - Stir in minced garlic and cook for 1 minute until fragrant.
03 - Add sliced mushrooms and sauté until they release moisture and begin to brown, about 5-7 minutes. Season lightly with salt and pepper.
04 - Stir in Arborio rice and cook, stirring frequently, until grains are well coated and translucent at the edges, about 2 minutes.
05 - Pour in white wine and cook, stirring, until completely absorbed.
06 - Begin adding warm vegetable broth one ladleful at a time, stirring frequently and allowing each addition to be absorbed before adding the next. Continue until rice is creamy and al dente, about 18-20 minutes.
07 - Remove from heat. Stir in remaining 1 tbsp butter, Parmesan cheese, and heavy cream. Adjust seasoning with salt and pepper.
08 - Drizzle with truffle oil and gently fold it in.
09 - Serve immediately, garnished with chopped parsley and extra Parmesan if desired.