Squash and Chestnut Lasagna

Name: Squash and Chestnut Lasagna
Ingredients: 1/4 pound pancetta, chopped; 1 medium yellow onion, minced; 2 tablespoons extra-virgin olive oil; 4 cloves garlic, minced; 2 teaspoons fresh sage leaves, chopped, plus additional leaves for garnish; 1 pound fresh chestnuts, shelled and skinned; 3 cups butternut squash or pumpkin pieces; 2 cups chicken stock; 1/2 teaspoon freshly grated nutmeg; 1 egg; 1 cup ricotta; Pasta Dough, recipe follows; 1 cup freshly grated pecorino cheese; 2 cups all-purpose flour, plus more for dusting; 1 teaspoon salt; 3 large eggs; Cornmeal, for dusting