Vinegar Pastry:
1 cup white rice flour
3/4 cup tapioca flour
3/4 cup cornstarch
1 rounded tsp xanthan gum
3/4 tsp salt
1 tbsp sugar
3/4 cup shortening
1 egg, lightly beaten
1 tbsp vinegar
2-3 tbsp ice water

directions:

In a medium bowl, whisk together the first 6 ingredients. Cut in shortening. Blend together the beaten egg, vinegar and water. Stir into the flour mixture, holding some back, until the pastry holds together and forms a ball. (Kneading will not toughen this pastry.)

Form 2 balls and place in a bowl; cover and refrigerate for 30 minutes. Remove and roll out, one at a time between 2 sheets of plastic wrap dusted with sweet rice flour. To place in pie tin: Remove top sheet and, using the other for ease of handling, invert the dough and drop it into the pan. Shape it into the curves before removing the second piece of plastic wrap. For crust to be used later, bake in a preheated 450 over for 10-12 minutes. For a filled pie, follow directions for that out.

-The Gluten-free Gourmet, Bette Hagman.