Creamy Baked Chicken and Wild Rice Casserole

Name: Creamy Baked Chicken and Wild Rice Casserole
Ingredients: 6 tablespoons unsalted butter, plus more for casserole dish; 5 cups water; 1 sprig fresh thyme; 1 bay leaf 2 tablespoons salt; 2 boneless, skinless chicken breasts; 1 1/3 cups wild rice; 6 tablespoons dark brown sugar; 1 cup cranberries, fresh or frozen; 2 tablespoons chopped fresh rosemary leaves; 1/4 cup bread crumbs; Salt; 5 ounces button mushrooms, quartered, (about 2 cups); 1 small onion, chopped; 2 1/2 cups heavy cream; 1/2 teaspoon ground cinnamon; 2 cups shredded Gruyere cheese; Freshly ground black pepper