This is a recipe I've modified from www.piginthekitchen.co.uk. If you do not need it to be gluten free then you can also make this recipe using regular pastry flour and no xanthan gum which I've also done and it turned out great. I've used it as a crust for apple pie and shoo fly pie. NOTE: this crust is slightly chewier than a regular pastry crust made with butter, if you want it to crisp up perhaps try brushing the edges with a non dairy spread.
- Cook the sweet potato by steaming or boiling, then mash it until smooth (discard skin). Put it in a bowl and refrigerate at least 2 hours before starting the pie.
- Put the rice flour, xanthan gum and baking powder into a large mixing bowl and stir them all together.
- Take the sweet potato out of the fridge and add the dry ingredients into the mash.
- Sprinkle the counter with a few tablespoons of rice flour and knead the dough until it's no longer sticky.
- Press the dough into a ball and then cover and refrigerate for another 30 minutes (I skip this step if I need to make the pie immediately).
- Take the dough out of the fridge and roll it out on a floured surface, then press it into your greased pie pan. (I sometimes need a spatula to help pick it all up at once, it's more fragile than regular pastry dough and may need a little help being transferred from the counter to the pan).
- Bake the shell right away or fill it first with the fruit or pie ingredients of your choice. Baking time depends on the kind of pie but it's usually around 40 minutes.