8 oz shiitake or cremini mushrooms, cleaned and sliced (if using shiitakes, discard stems)
1 tbsp garlic, roughly chopped
3/4 cup arborio rice
1/2 cup dry white wine
3/8 cup Parmesan cheese, grated, divided use
1/2 tsp thyme
1 tbsp unsalted butter
Salt and freshly ground pepper
Truffle oil, for drizzling, optional
1 tbsp parsley, chopped
Bring the stock to a simmer in a small saucepan over medium-high heat. Reduce the heat to low, cover, and keep the stock hot.
Heat the olive oil in a large heavy-bottomed saucepan over medium-high heat. Add the onion and saute, stirring frequently with a wooden spoon for 2 minutes. Add the mushrooms and cook until tender and slightly brown, about 8 minutes. Add the garlic and cook for 2 minutes more. Add the rice and stir well, about 30 seconds. Add the wine and simmer, stirring constantly until the liquid is absorbed, 2 to 3 minutes. Add 3/4 cup of the hot stock, reduce the heat to medium, and cook, stirring frequently, until the stock is absorbed. Add the remaining hot stock 3/4 cup at a time, stirring frequently and allowing each addition to be fully absorbed before adding more, until the rice is just tender and the risotto is creamy. The total cooking time is 20 to 25 minutes.
Stir in 1/4 cup cheese, the thyme, and butter. If the rice appears dry, add up to 1/4 cup water to loosen the risotto slightly. Season with salt and pepper to taste.
Divide the risotto between 2 large bowls and drizzle with truffle oil, if desired. Sprinkle with the remaining 2 tablespoons cheese and the chives.