In a bowl, mix together the flour and salt. Use a fork to cut the shortening into the flour until pea-sized crumbs form. Add the water, 2 tablespoons at a time, and mix until a dough forms. Divide the dough in half, form into a disk and wrap with plastic wrap to store in the refrigerator for at least 30 minutes.
Fill a separate bowl with the berries, sugar and cornstarch, and toss until the berries are evenly coated. Set aside for 10 minutes. Meanwhile, preheat the oven to 375°F (190°C).
On a lightly floured surface and with a floured pin, roll out the dough to 12-inch (30cm) circles. Place one crust into the bottom of a 9-inch (23cm) pie plate, fill with the berry mixture and top with the other pie crust, using the design of choice. Trim the dough to 1 inch past the pie plate. Tuck the ends under the bottom crust and pinch or crimp to seal. Cut vents, as needed.
Whisk the egg and water together. Use a pastry brush to apply the egg wash to the pie crust.
Bake the pie for 50-55 minutes or until the crust is golden. Transfer to a wire rack to cool completely before serving.
Notes
If the pie crust begins to brown too quickly, use foil to cover the edges of the crust.