Peel and dice the rutabaga, potatoes, onion, and carrots into small pieces.
In a 6-quart Dutch oven or large pot, melt the butter and add all the diced vegetables. Add in the herbs and seasonings. Cover and cook over medium heat for 30 minutes.
Add in cooked ground beef (I keep cooked meat in the freezer), you can cook this in a separate pan and add to the vegetables.
Stir the cornstarch into the beef broth and add to the pot. Cook uncovered for an additional 10-15 minutes until the rutabaga is softened. Add in the peas and stir. Take off the heat and cool to room temperature.
Take each pie crust and divide the dough into 8 equal pieces for a total of 16 pieces. Shape the pieces into balls and roll them out into circles with a rolling pin on a floured work surface. Place 1/2 cup of the rutabaga potato mixture onto each pastry circle. Fold one side over forming a half circle.
Twist or crimp the edges together and make a couple of small slits on top of each pasty. I freeze half of the pasties (8) to eat another time.
Line a baking sheet with parchment paper and set the pasties on it. Combine the egg and water and brush onto the dough with a pastry brush.
Heat the oven to 400 degrees and bake for 25-35 minutes until golden brown.