Place flour, sugar and salt in a food processor fitted with the steel blade. Pulse the mixture to combine. Add butter and shortening; pulse until the fat is evenly cut in and the mixture resembles coarse cornmeal. Transfer mixture to a mixing bowl. Working quickly, gradually add enough cold water while tossing and stirring with a fork so the dough just begins to stick together. Divide dough into two equal-size portions, flatten into rounds, wrap in plastic and chills several hours or overnight.
Preheat oven to 400° F.
In a large bowl, combine all the filling ingredients except the egg yolk and water; toss gently to mix well. Working quickly, roll out the bottom crust. Fit it into a 9-inch glass pie plate. Place filling into the crust, mounding it slightly in the center.
Roll out top crust. Trim the excess overhang from the bottom crust and brush the remaining edge lightly with water. Cover the filling with the top crust. Fold the edge of the dough under the pie, pressing well to seal. Scallop the edge of the crust.
Combine egg yolk and water. Brush the crust with the glaze. Cut steam vents in the top crust. Place pie plate on a baking sheet or aluminum foil to catch possible juice spills. Bake for 30 minutes.
Reduce the heat to 375° F, and bake an additional 20 to 30 minutes or until the juices are bubbling and the crust is golden brown.Makes 4