In a medium saucepan, heat the chicken or vegetable broth over low heat. Keep it warm throughout the cooking process.

In a large skillet, heat the olive oil and 1 tablespoon of butter over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes.

Stir in the minced garlic and sliced mushrooms. Cook until the mushrooms are tender and browned, about 5-7 minutes.

Add the Arborio rice to the skillet, stirring to coat the grains with the oil and butter. Cook for 1-2 minutes until the rice is slightly translucent.

Pour in the white wine and cook, stirring frequently, until the liquid is mostly absorbed.

Begin adding the warm broth, one ladle at a time, stirring frequently. Wait until the liquid is mostly absorbed before adding the next ladle. Continue this process for about 18-20 minutes, or until the rice is creamy and al dente.

Once the rice is cooked, remove the skillet from heat. Stir in the remaining tablespoon of butter, heavy cream, Parmesan cheese, and truffle oil. Season with salt and pepper to taste.

Let the risotto sit for a couple of minutes to thicken. Serve warm, garnished with chopped parsley.