Melt 5 tablespoons unsalted butter in a large skillet over medium heat. Add ½ cup finely diced yellow onion and ½ cup diced celery. Cook for 4 to 5 minutes, stirring occasionally, until the vegetables are softened.

Sprinkle ⅓ cup all-purpose flour, 1 teaspoon poultry seasoning, ½ teaspoon garlic powder, ½ teaspoon kosher salt, and ½ teaspoon ground black pepper over the vegetables. Cook for 1 minute, stirring constantly, until the flour has absorbed the butter and evenly coats the vegetables. Do not let the flour brown.

Slowly pour in 1¾ cups low-sodium chicken broth, whisking or stirring constantly to keep the sauce smooth. Stir in ½ cup whole milk. Bring the mixture to a gentle simmer and cook for 3 to 5 minutes, stirring frequently, until the sauce is thick and creamy enough to coat the back of a spoon.

Stir in 2½ cups rotisserie chicken and 1½ cups thawed and drained frozen peas and carrots. Cook for 2 to 3 minutes, stirring occasionally, just until everything is heated through. Remove the skillet from the heat. Taste the filling and add additional kosher salt if needed. Let the filling stand for about 5 minutes while you prepare the crust.

Unroll 1 refrigerated pie crust and gently fit it into a 9-inch pie dish, pressing it against the bottom and sides without stretching the dough. Place the pie dish on a rimmed baking sheet, then spoon the chicken filling evenly into the crust.

Place the remaining refrigerated pie crust over the filling. Fold the edge of the top crust under the edge of the bottom crust and press or crimp the edges together to seal. Cut 4 to 5 small slits in the center of the top crust to allow steam to escape.

Whisk 1 large egg with 1 tablespoon water in a small bowl until blended. Lightly brush the egg wash over the top crust using a pastry brush.

Bake for 15 minutes, then loosely cover the outer edge of the crust with foil strips to prevent overbrowning. Continue baking for 15 to 25 minutes, until the crust is golden brown and the filling is bubbling through the vents.

Let the chicken pot pie rest for at least 15 minutes before slicing. The filling will continue to thicken as it rests, making the pie much easier to serve. Serve warm and ENJOY!