1. Heat the olive oil in a large saucepan. Add finely chopped garlic and onion. Cook over medium heat for 5 minutes, until softened.
2. Add mushrooms and 1 mushroom stock cube, cook for a few minutes, occasionally stirring until the mushrooms have softened.
3. Add 1 cup arborio rice, turn up the heat and stir to coat.
4. Pour wine into rice mixture. Cook and stir until liquid is absorbed. Once the wine has cooked into the rice, turn the heat down.
5. Pour ½ cup hot, boiled water. Simmer the rice, stirring often, until the rice has absorbed all the liquid.
6. Continue adding about the same amount of hot water until all the liquid has been absorbed and the rice is plump and tender.
7. Add truffle oil and stir. Season with salt and black pepper. Garnish with chopped fresh parsley.