n n n Bring the vegetable broth to a simmer in a medium saucepan. Keep the broth warm over very low heat.n n n n Meanwhile, add the olive oil, 1 tablespoon of butter, and the diced onion to a heavy large saucepan. Cook, stirring occasionally, for about 5 minutes over medium heat.n n n n Add the mushrooms and garlic, and cook until all of the liquid evaporates and the mushrooms start to brown slightly (about 10 minutes).n n n n Stir in the rice and let it toast for a few minutes. Add the wine and cook, stirring continuously, until fully absorbed.n n n n Add 1 cup of the hot vegetable broth to the rice, and stir until the broth is absorbed. Continue adding broth, 1 cup at a time, stirring continuously, until the rice is just tender and the risotto is smooth and creamy (about 25-30 minutes).n n n n Turn off the heat, and taste if your risotto needs salt.* Add some, if necessary. Stir in the remaining 3 tablespoons of butter and Parmesan cheese. Let rest for 5 minutes. Serve.n nn