Preheat oven to 400 degrees.
Preheat a large skillet over medium heat. I like to use a cast-iron skillet.
Once hot, add the ground beef and season with salt and pepper. Cook beef for approximately 5 minutes, until it is no longer pink, then remove it from the skillet.
Add olive oil, diced onions, celery, carrots, and sliced mushrooms to the hot pan—season with more salt and pepper.
Sauté for 8-10 minutes, stirring occasionally, until the vegetables are tender. If the mix is too dry, add a bit more oil. You'll know by the aroma when they are ready.
Add the minced garlic and cook another minute, stirring so the bottom doesn't burn.
Stir in the flour so that the vegetable mixture is fully coated, then slowly stir in the beef broth.
Bring to a simmer and cook for 3-5 minutes until thickened.
Add basil, oregano, Worcestershire, and heavy cream.
Return the cooked beef to the skillet, then stir in the frozen peas. Adjust salt and pepper to taste.
Roll out the pie crusts to fit a 9"x11" baking dish or average pie plate, pressing the bottom crust into place.
Pour the beef mixture into the baking dish, then cover the top with the second crust.
Score the pie crust with a knife to release steam.
Whisk together the egg and water, then brush the top crust evenly. This gives the crust a lovely golden shine.
Bake in the preheated oven for 30 to 40 minutes until the crust is golden brown and the filling is bubbly.
Let the pot pie cool for 20 minutes. This time will allow the filling to thicken more, making it easier to serve.