Place dried porcini mushrooms in a medium bowl and cover with 1 1/2 cups boiling water. Let soak for at least 15 minutes. Drain mushrooms, reserving 1 cup of the soaking liquid. Chop mushrooms and set aside.

Preheat an oven to 400°F. Place wild mushrooms, 4 garlic cloves and thyme sprigs on a baking sheet. Toss with 3 tablespoons olive oil, then sprinkle with salt and pepper. Roast, tossing occasionally, until soft and golden brown (20 - 25 minutes). Discard garlic and thyme sprigs, then season mushrooms to taste with more salt and pepper. Set aside.

Add mushroom soaking liquid to chicken stock, and bring to a simmer in a medium saucepan over medium heat. Once simmering, reduce heat to low, and keep warm.

In a large, heavy-bottom pot, warm 1 tablespoons olive oil and 1 tablespoon butter over medium heat. Add the onion along with a pinch of salt, and cook until the onion is tender but not browned (5 to 6 minutes). After 3 minutes add the garlic and chopped thyme. Stir in the rice and cook for 2 minutes, then add the white wine and cook for 1 more minute. Add 1 cup of warm chicken stock and a pinch of salt, and cook, stirring occasionally, until all of the liquid has been absorbed. Continue adding warm chicken stock 1/2 cup at a time, waiting until the stock is absorbed before adding again, and stirring frequently to make sure the bottom doesn’t burn. Continue until the rice is cooked through, but still al dente, about 30 - 35 minutes total. You may not use all of the chicken stock. During the last addition, stir in the chopped porcini mushrooms and 1/2 the roasted mushrooms.

Take the risotto off the heat, and stir in Parmesan cheese and remaining 2 tablespoons butter. Season to taste with salt and black pepper.

To serve, spoon risotto in a shallow bowl and top with reserved roasted mushrooms, a sprinkling of Parmesan cheese and a few turns of black pepper.