Winter Squash Risotto

Name: Winter Squash Risotto
Ingredients: 5 cups reduced-sodium chicken broth, or vegetable broth; 2 tablespoons extra-virgin olive oil; 3 medium shallots, thinly sliced; 3 cups chopped peeled butternut, hubbard, red kuri or kabocha squash (1/2-inch pieces); 2 cups shiitake mushroom caps, thinly sliced; ½ teaspoon dried thyme; ½ teaspoon salt; ¼ teaspoon freshly ground pepper; 1/8 teaspoon crumbled saffron threads, (optional); 1 cup arborio rice; 1/2 cup dry white wine, or dry vermouth; ½ cup finely grated Parmigiano-Reggiano cheese