Make the Crust

1. Pulse flour, sugar, salt and butter until butter is the size of coarse crumbs. Add water and pulse until dough begins to come together
2. Flour work surface.  Form into a log. Will make 3 shells. If not using all of the crust, it may be wrapped and kept in freezer for several months
3. Take ⅓ of dough recipe and place on floured surface. Press into a disc and then roll out until it is big enough to fit into the pie pan

Prepare Filling & Bake

1. In a large bowl, add blueberries, strawberries and raspberries, sugar, cornstarch and lemon zest. Mix gently
2. Pour into bottom layer of pie dough
3. Take another ⅓ of dough and roll into a disc.  Cut lattice strips with a pastry cutter. Weave top layer of dough in lattice fashion and pinch dough all the way around to seal
4. Brush with egg wash, sprinkle with sugar
5. Place on parchment-lined baking sheet and bake at 375º (regular oven) or 325º (convection oven) for 1 hour.  Pie is cooked when juices are thick and syrupy.  Let cool about 2 hours before serving

Note:  Extra pie dough can be double-wrapped and frozen for later use.