Preheat the oven to 425° and lightly spray a deep dish pie plate with non-stick cooking spray.
Roll out dough on a lightly floured surface.
Take one pie crust and place it into the bottom of the prepared pie plate. Set the top pie crust aside temporarily.
In a large frying pan, melt 2 tablespoons of butter over medium heat. Add beef to the pan, sprinkle with Slap Ya Mama seasoning, garlic powder, pepper, and paprika. Cook until the steak is browned. Remove from the pan and set aside.
In the same pan, melt the remaining 2 tablespoons of butter. Add the onions, celery, and garlic. Cook until the onions are transparent and celery is tender, stirring frequently.
Next, add beef back to the pan, sprinkle with flour and let cook for 2 minutes.
Gradually pour beef broth and heavy cream into the pan, stirring frequently until hot and thickened.
Next, add the thawed vegetables, and cheese. Stir and let cook for 5 minutes.
Spoon pot pie mixture into prepared pie plate and top with remaining pie crust.
Seal and flute edges, and cut several slits into the top of the pie crust.
In a small bowl, whisk egg and water together and brush over the pot pie.
Bake for 35-40 minutes or until the crust is golden brown.
Remove from the oven and enjoy!