Day 1: In a large mixing bowl, combine the active sourdough starter, salt, and water. Mix well.
Add the flour and mix until completely incorporated (all flour absorbed). Cover and rest in a warm environment for 30 minutes.
Perform one fold, as explained. Imagine the bowl divided into 4 corners. Gently scoop from the bottom and lift up one corner without the dough breaking as high as it’ll go, then fold toward the center of the dough. Rotate the bowl to the next “corner” and repeat. Repeat for a total of 10 times.
Cover and rest the dough in a warm environment for 4-12 hours, until doubled in volume.
Drizzle 2 tbsp. olive oil in the bottom of a 9×13″ baking dish. I also recommend lining the bottom with parchment paper to prevent anything problems when baking.
Rub your hands with a little olive oil, then gently remove the dough from the sides of the bowl to transfer to the prepared baking dish.
Fold like an envelope and place seam-side down.
To continue baking same day, skip this step. Cover the baking dish with Saran Wrap and place in the fridge overnight.