1. Preheat your oven to 375 degrees.

Pie Crust:

1. In bowl whisk together the flour and salt.
2. With a pie cutter, cut in the shortening until the mixture is like coarse sand.
3. Sprinkle in water, 1 tsp or so at a time, mixing lightly with a fork.
4. Press into a ball.
5. Separate the ball into 2 balls: use one for the beef pot pie, and freeze one for later.
6. On a piece of parchment paper roll out one ball of the dough to fit a 9 inch pie plate.
7. Set aside.

Beef Filling:

1. In a skillet add 2 tbsp of oil over low-medium heat, then add the diced onion, carrots, celery, and potatoes.
2. Season with salt, pepper and thyme.
3. Cook until the onion, carrots, celery, and potatoes are softened.
4. Then stir in the gravy and Worcestershire sauce and let simmer on low for about 5 minutes.
5. Add the cooked chopped beef and let simmer for about 10 minutes.
6. Stir in the additional vegetables (1 cup leftover or frozen veg).
7. Add the beef filling to a 9 inch pie plate.
8. Cover with the pie crust (I lightly press the crust down on to the filling), then trim the edges.
9. Add steam vents to the top of the crust.
10. Place the pie in the oven, and put a baking sheet on a separate rack under the pie, to catch any drippings.
11. Bake for about 1 hour, or until the crust is golden brown and the filling is bubbling.
12. Let sit for a few minutes before serving.