Combine flour blend, sugar, xanthan gum and salt in bowl. Cut in butter and shortening with pastry blender or fork until mixture resembles coarse crumbs.
Combine egg, cold water and apple cider vinegar in another bowl; beat with fork until mixed. Add egg mixture to flour blend mixture; stir just until moistened. Shape pastry into a ball; flatten slightly. Wrap in plastic food wrap; refrigerate at least 1 hour or until chilled.
Remove from refrigerator; let stand 15 minutes at room temperature. Unwrap pastry; place onto parchment paper lightly floured with gluten-free flour blend. Lightly flour pastry with gluten-free flour blend; top with another sheet of parchment paper. Roll out pastry into 12-inch circle. Transfer pastry to ungreased 9-inch pie pan, pressing firmly against bottom and sides and sealing any cracks as necessary. Crimp or flute edge. Fill and bake as directed in pie recipe.
Gluten-Free Flour Blend
: Combine 2 cups rice flour, 2/3 cup potato starch, 1/3 cup tapioca flour and 1 teaspoon xanthan gum. Use appropriate amount for recipe; store remainder in container with tight-fitting lid. Stir before using.
This recipe was developed using alternative flours and products labeled as “gluten-free.” The best source for additional information is the ingredient listing on product packaging. Learn about gluten-free baking