Chicken Pot Pie Homemade "Hot Pockets"

Preheat oven to 350 degrees F and line a baking sheet with parchment paper. On a floured work surface, roll out pie crust into a large rectangle and slice off rounded edges (if using store-bought). Slice into four strips. Place cooked chicken and vegetables in a large mixing bowl. In a small saucepan over low heat, whisk flour and milk and let simmer, 5 minutes until thick. Pour sauce over chicken and vegetables and season generously with salt and pepper. Spoon mixture over bottom halves of pie crust strips and fold over tops. Use your fingers to pinch to seal and press the twines of a fork to crimp. Brush with egg wash and transfer to prepared baking sheet. Bake until golden and puffy, 18 to 20 minutes.