Mix tapioca flour, brown rice flour, sorghum flour, almond meal, cornstarch, sugar, xanthan gum, baking powder, and salt together in a bowl. Cut in diced shortening using a pastry blender or two knives until pebble-size pieces form.
Whisk water, egg replacer, and vinegar in a small bowl; stir into flour mixture until a loose dough forms.
Roll out dough to even thickness on a piece of parchment paper and transfer to a 9-inch pie plate, or press dough evenly into the pie plate.
Bake in the preheated oven until golden, about 15 minutes.