Shortcut Fried Chicken and Dumplings

Name: Shortcut Fried Chicken and Dumplings
Ingredients: 2 cups all-purpose flour, plus more for dusting (see Cook's Note); 5 teaspoons baking powder; 2 1/4 teaspoons sugar; Kosher salt; 9 tablespoons unsalted butter, cut into small pieces and frozen; 3/4 cup buttermilk; 4 cups low-sodium chicken broth; 2 cups prepared mashed potatoes with gravy; 3 cups chopped fried chicken, bones removed and discarded (from about 1 pound of bone-in chicken); One 10-ounce bag frozen peas and carrots, thawed