Chicken and Herb Dumplings

Name: Chicken and Herb Dumplings
Ingredients: 7 tablespoons cold unsalted butter; 2 carrots, chopped; 2 stalks celery, chopped; 1 parsnip, peeled and chopped; 1 bay leaf; Kosher salt and freshly ground pepper; 1 1/2 cups plus 3 tablespoons all-purpose flour; 4 cups low-sodium chicken broth; 2 teaspoons baking powder; 2/3 cup cold buttermilk; 1 tablespoon chopped fresh dill, plus more for topping; 1 tablespoon chopped fresh chives, plus more for topping; 2 cups shredded rotisserie chicken, skin removed