Blend the oats in a blender until it is a course flour.
Add the oat flour, almond flour, flax meal, tapioca starch and baking powder to a bowl and stir.
Add the mashed sweet potato and cut in with a pastry cutter or fork until mixture starts sticking together and is mixed well. Press into a ball with hands.
Place 2/3 of the dough ball on a piece of parchment. Place another piece of parchment on top of the dough ball and roll it out to about a 1/4 inch thickness.
If you are using a 9 inch pie plate: Flip pie plate over and place it on top of the rolled out dough. Using a knife cut around the pie plate adding about an inch extra around the pie plate.
Turn the pie plate over and place the dough disk gently into the pie plate just like you would if making a pie, leaving the excess dough around the top edge. We will trim that later.
If using the mini pie plates: Use the same technique as the larger pie plate.
Before spooning the filling into the crusts, stir the arrowroot flour into the 1/2 cup of vegetable broth and then stir it into the filling mixture.
Spoon the filling into the crust going up to the level of the top of the pie plate.
Roll out the remaining dough just like you did for the bottom layer of crust.
Cut a circle of dough to fit onto the top of the pie.
Gently place it on top of the filling making sure it reaches almost to the outside edge of the pie plate. Gently press the two layers of crust together to seal the filling in and then create a nice pie edge by pressing and pinching the dough with your fingers. Trim off any excess dough that is hanging past the pie plate edge.
Make three small slices through the top crust toward the center of the pie to allow steam to escape while baking.
Bake for 35 minutes.
If you want to brown the top a bit, turn the oven to the broil settling and watch very carefully until it reaches the desired brownness.
If using the mini pie plates: Let pies cool for at least 20 minutes before trying to pop them out of their pans.
Store in airtight container in the fridge for up to 5 days.