The previous night, add the yeast and water to a large mixing bowl. Add in the unfed sourdough starter, salt, and the flour one cup at a time, stirring frequently. The dough should be shaggy when finished. Cover with a tea towel and allow dough to rise for 8-18 hours.
Transfer the dough to a floured proofing bowl or to a glass bowl, and lightly dust with flour. Allow dough to rest for another hour.
Fill the sink with lukewarm water. Submerge clay pot, and soak for 15 minutes. Remove the clay pot from the water and towel dry. Place the clay pot in a room-temprature oven.
Preheat the oven to 425 degrees with the clay pot inside.
Once oven reaches temperature, remove the clay pot from the oven, add parchment paper (optional) to the bottom and add the dough to the pot, and place back in the oven with the top on for 30 minutes.
Carefully remove the lid, and allow the bread to bake uncovered for another 10 minutes. Oven temperatures can vary, so if your bread hasn't browned after 10 minutes, you can bake it uncovered for an additional 5-10 minutes until it reaches the color you prefer.
Remove from oven, place the bread on a clean surface to cool, and wait 30 minutes before slicing!
