Mill the grains, add sugar and salt and mix.
Chop up the butter into small cubes and add to the flour mixture.
After all your butter gets cut in, the dough should be very crumbly and butter should be pea sized chunks.
Add the sourdough starter and mix until combined.
Separate the dough and shape it into 2 round flat disks.
Wrap in parchment paper and place inside of a bag in the fridge to chill.
If you want a full ferment: chill for 2-3 days. If you want to use right away: chill for at least 30 mins but best is 2 hours.
When ready to bake, roll out and place into a pie pan, fill with your favorite fillings.
Bake at 400*F for 35-40 mins.