In a medium bowl, stir together cake flour, all-purpose flour, and salt. Using a pastry blender, cut in butter and shortening until pieces are pea-size.
In a small bowl, stir together 4 tablespoons of the water, egg, and lemon juice. Using a large fork, gently toss the flour mixture and egg mixture together. If there are any dry parts, add the remaining 1 tablespoon of water and gently toss to moisten evenly (should be a mass of very large crumbs).
Turn crumb mixture out onto a lightly floured surface. Using your fingers, gently form a ball. Using just a bit of flour, knead 4 to 5 times to form a ball. Using your hands, flatten into a disc about 1 inch thick. If necessary, wrap the dough in plastic wrap and chill in the refrigerator for 1 to 2 hours or until easy to handle.
On a lightly floured surface, roll dough from center to edges into a circle 12 inches in diameter. To transfer pastry, wrap it around the rolling pin. Unroll pastry into a 9-inch pie plate. Ease pastry into pie plate without stretching it and gently fit pastry into dish.
Trim the overhang to an even 1 inch all the way around. Tuck the crust under and flute the edges. Bake as directed in individual recipes. Makes 1 pie crust