Ghost pot pie

INGREDIENTS
For pie dough:
1 (120g) cup all-purpose flour
1 teaspoon Diamond Crystal® Kosher Salt
1/4 cup plus 2 tablespoons unsalted butter, cold and cubed
2 tablespoons ice water
2 teaspoons apple cider vinegar
For filling:
3 tablespoons unsalted butter
1 cup diced carrots
½ cup diced onion
½ cup diced celery
¼ cup all-purpose flour
2 cups low-sodium chicken broth
1 cup whole milk
1-pound boneless, skinless chicken breasts, cooked and diced
1 cup frozen peas
1 cup diced potatoes
1 teaspoon dried thyme
½ teaspoon Diamond Crystal® Kosher Salt
¼ teaspoon ground black pepper
2 sheets puff pastry dough, thawed
1 egg, beaten, for egg wash
DIRECTIONS
For pie dough: Combine flour and kosher salt. Cut in butter using pastry cutter or your fingers until mixture resembles coarse crumbs. Add ice water and vinegar and mix until dough comes together. Pat dough into flattened disc and wrap tightly with plastic wrap. Refrigerate dough for at least 30 minutes, or until chilled.
For filling: Melt butter in large skillet over medium heat. Add carrots, onion and celery, and cook until soft about 5-7 minutes. Stir in flour and cook 1-2 minutes, until no lumps remain. Whisk in broth and milk, stirring vigorously, until smooth.
Bring mixture to simmer and add chicken, peas, potatoes, thyme, kosher salt and pepper. Cook, stirring occasionally, until potatoes are softened slightly, and mixture thickens. Remove from heat and set aside.
Preheat oven to 375°F. Roll out dough on lightly floured surface to 12-inches in diameter. Carefully transfer dough to pie dish, pressing into bottom and sides. Fold excess dough under shell to create crust and crimp to make decorative edges.
Roll out puff pastry dough to about 1/4-inch thickness, and using cookie cutter or sharp knife, cut out ghost shapes. Use small end of round piping tip to cut out eye and mouth holes if desired.
Pour filling into prepared crust and top with ghost shapes, as desired. Brush ghosts and crust with egg. Bake until crust is golden-brown, and filling is bubbling around edges, about 40-45 minutes.
If ghosts begin to brown too quickly, use tin foil to cover. Let cool for at least 10 minutes before serving.
Happy Halloween!