Preheat the oven to 400 degrees F (200 degrees C).

Make pie crust: Combine flour and salt in a bowl. Mash shortening into flour mixture with a pastry cutter or fork until mixture is crumbly. Gradually add cold water as needed, tossing with a fork until dough forms a ball. Wrap dough in plastic wrap and refrigerate for 30 minutes.

Turn dough out onto a flat work surface dusted with flour. Divide dough in half and form each half into a ball. Roll one dough ball into a circle 2 inches larger than the pie plate and about 1/8-inch thick. Wrap dough around the rolling pin, starting on one side of the circle. Unroll over the pie plate and trim dough. Roll out remaining dough ball into a circle large enough to fit the top of pie; set aside.

Beat egg white and 1 tablespoon water; brush over the bottom of crust and set aside.

Make filling: Combine sugar, cornstarch, lemon peel, vanilla extract, and cinnamon in a bowl. Gently stir in blueberries and raspberries to coat; pour into crust. Top with reserved pie crust and seal edges.

Brush the top crust with 1 tablespoon water; sprinkle 1 tablespoon sugar on top. Cut a few slits into the top crust with a sharp knife.

Bake in the preheated oven until crust is golden brown and filling is bubbly, about 45 minutes. Set pie onto a wire rack to cool completely before refrigerating.