Combine the butter, shortening, 2 cups of the cake flour, and 1 cup of the all-purpose flour. Blend together. Stop mixer, scrape the sides and add remaining 2 cups of cake flour and remaining 1 cup of all purpose flour. Blend to combine completely. Mix sugar and salt into 1/4 cup of the water and add it to the flour mixture. Blend briefly and add the remaining water if needed. The dough should not be overworked and should make a solid piece when held in your hand. Turn the dough out onto a lightly floured smooth surface and knead it several times. Divide the dough into portions and flatten it. Wrap unused dough in plastic. Roll out the dough to fit a 9-inch pie pan.

Preheat oven to 475 degrees F. Prick bottom and sides of pastry with fork. Bake 12 minutes or until light brown. Cool on wire rack.