8 cups canned low-salt chicken broth 1/2-ounce dried porcini mushrooms 1/4 cup unsalted butter 2 tablespoons olive oil 2 cups finely chopped onions 10 ounces white mushrooms, finely chopped 2 garlic cloves, minced 1 1/2 cups Arborio rice or short-grain white rice Juice of 2 freshly squeezed lemons 2/3 cup grated Parmesan Salt and freshly ground black pepper, optional
1 Bring the broth to a simmer in a heavy medium saucepan. Add the porcini mushrooms. Set aside until the mushrooms are tender, about 5 minutes. Keep the broth warm over very low heat.
2 Melt the butter in a heavy large saucepan over medium heat. Add olive oil. Add the onions and sauté until tender, about 8 minutes. Add the white mushrooms and garlic.
3 Using a slotted spoon, transfer the porcini mushrooms to a cutting board. Finely chop the mushrooms and add to the saucepan. Sauté until the mushrooms are tender and the juices evaporate, about 5 minutes.
Stir in the rice and let it toast for a few minutes. Add the lemon juice; cook until the liquid is absorbed, stirring often, about 2 minutes. Add 1 cup of hot broth; simmer over medium-low heat until the liquid is absorbed, stirring often, about 3 minutes. Continue to cook until the rice is just tender and the mixture is creamy, adding more broth by cupfuls and stirring often, about 28 minutes (the rice will absorb 6 to 8 cups of broth). Mix in the Parmesan. Season with salt and pepper, to taste.