In food processor, place flours, cornmeal, 2 tablespoons sugar, the xanthan gum, 1/2 teaspoon salt and the pumpkin pie spice. Cover; pulse, using quick on-and-off motions, until blended. Add 1/2 cup butter and the shortening. Cover; pulse until coarse crumbs form, about 5 seconds. Add water; pulse just until dough comes together. Divide dough in half; flatten each into a disk. Wrap in plastic wrap; refrigerate until firm.