Heat the olive oil in a frying pan over medium heat. Add the onion and garlic and sauté until tender.
Add the mushrooms and continue cooking until browned. Set aside.
Heat the chicken stock in a saucepan over medium heat.
In a separate saucepan, heat the Guénard truffle oil over medium heat. Add the rice and stir to coat with the oil. Add the white wine and stir until completely absorbed.
Add a ladleful of hot stock to the rice and stir until completely absorbed. Repeat with the remaining stock, one ladle at a time, until the rice is cooked but still slightly al dente.
Add the mushroom mixture and grated Parmesan to the rice. Stir until the cheese has melted and everything is well combined. Season with salt and pepper to taste.
Leave the risotto to sit for 2-3 minutes before serving hot. Garnish with fresh mushrooms and a spoonful of Guénard truffle oil.