For broth: Discard chicken giblets. In a stockpot, combine chicken, parsley sprigs, celery stalks, halved carrots, and quartered onion. Add water to cover by 1 inch. Bring to a gentle boil over medium-high heat. Reduce heat to medium, and simmer until an instant-read thermometer inserted in thickest portion of chicken registers 165°, about 1½ hours.
Remove chicken from broth. Let stand until cool enough to handle. Remove meat, and coarsely chop. Discard skin and bones. Strain broth through a fine-mesh sieve into a bowl, discarding solids. Reserve 4 cups meat and 1¾ cups broth for pie. Reserve any remaining meat and broth for another use.
Preheat oven to 400°.
For filling: In a 10-inch cast-iron skillet, melt butter over medium heat. Add beans, chopped carrot, corn, chopped onion, and chopped celery. Cook, stirring occasionally, until softened, 10 to 12 minutes.
Sprinkle flour over vegetable mixture; cook, stirring frequently, for 1 minute. Stir in reserved 1¾ cups broth and cream. Cook, stirring constantly, until mixture begins to thicken. Stir in reserved 4 cups chicken, parsley, salt, sage, thyme, garlic powder, and pepper. Remove from heat.
On a lightly floured surface, roll Pie Dough into a 12-inch circle. Gently place over hot chicken mixture. Fold excess dough under, and crimp as desired.
In a small bowl, whisk together egg and 2 teaspoons water. Brush egg wash onto dough. Sprinkle with salt. Place skillet on a baking sheet.
Bake until crust is golden brown and filling is bubbling, about 30 minutes. Let stand for 10 minutes before serving.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/chicken-pot-pie/