Celery Root and Mushroom Lasagna

Name: Celery Root and Mushroom Lasagna
Ingredients: 1 cup dried porcini mushrooms; 2 cups boiling water; 4 tablespoons unsalted butter; 1/4 cup extra-virgin olive oil; 3/4 pound white mushrooms, thinly sliced (4 cups); Salt and freshly ground white pepper; 1/4 pound thickly sliced prosciutto di Parma, cut into 1/4-inch dice; 2 medium shallots, finely chopped; 1 fresh bay leaf; 2 rosemary sprigs; 2 sage sprigs; 2 thyme sprigs; 1 pound celery root, peeled and finely diced (1 1/2 cups); 3 medium leeks, white and tender green parts only, finely chopped (3 cups); 1/2 cup dry Marsala; 4 cups chicken stock or low-sodium broth; 2 1/2 cups heavy cream; 1 3/4 cups freshly grated Parmigiano-Reggiano cheese; 2 large eggs; 1 1/2 pounds lasagna noodles; 1 1/2 pounds fresh mozzarella, thinly sliced; 1 cup basil leaves