Chicken Noodle Casserole

Name: Chicken Noodle Casserole
Ingredients: 2 pounds skin-on, bone-in chicken breast; 4 cups low-sodium chicken broth; 4 black peppercorns; 3 1/2 teaspoons salt, divided; 1 bay leaf; 2 parsley sprigs , divided; 12 ounces extra-wide egg noodles; 1/2 medium onion, finely chopped; 2 stalks celery, finely chopped; Pinch ground black pepper; 4 tablespoons (1/2 stick) unsalted butter , at room temperature; 6 tablespoons all-purpose flour; 1/3 cup whole milk; 1/3 cup sour cream; 1 (4-ounce) jar chopped pimentos , drained; 2 cups ( 8 ounces ) grated sharp cheddar cheese