We used black trumpets, chanterelles, and cauliflower mushrooms, but any wild mushroom or a combination will give this risotto a rich, intense flavor.
Gently clean the mushrooms with a mushroom brush or paper towel. Trim tough stems, and discard. Cut mushrooms into 1/2-inch pieces.
Melt 2 tablespoons butter in a large skillet over medium-high heat. Add chanterelles, season with salt and pepper, and saute, stirring occasionally, until softened, about 3 minutes. Transfer to a bowl. In the same skillet, melt 2 tablespoons more butter; add the remaining mushrooms, season, and cook, stirring occasionally, until softened, about 2 minutes. Transfer to bowl with chanterelles.
Heat chicken stock in a saucepan over medium heat, then reduce to a low simmer. Meanwhile, heat the olive oil in a heavy-bottomed saucepan over medium heat. Add the shallots, and cook, stirring, until translucent, about 3 minutes. Add the rice, and cook, stirring, until it begins to make a clicking sound like glass beads, 3 to 4 minutes. Add the wine, and cook, stirring, until absorbed by the rice. Ladle 3/4 cup hot stock into pan. Using a wooden spoon, stir the rice mixture constantly, at moderate speed. When it is just thick enough to leave a clear wake behind the spoon, add 3/4 cup more stock. Continue adding stock, 3/4 cup at a time, and stirring constantly until the rice is al dente but not crunchy. (The rice should be mostly translucent but still opaque in the center.) Remove from heat. Stir in the remaining 4 tablespoons butter, the reserved mushrooms, and 1 cup Parmesan. Season with salt and pepper.
Divide the risotto among four shallow bowls, mounding it in the center. Grate or shave additional Parmesan over the risotto, and sprinkle with chervil. Serve.
