Prepare the Sourdough Starter in advance. In a large bowl, use a large spoon or rubber spatula to stir together the starter, water and olive oil.
To the bowl add the flour and salt. Use a nonstick rubber spatula or a wooden spoon to combine the ingredients. Please Note: The dough won’t be soft but rather shaggy, this is okay and completely normal. Don’t over-mix the dough, just make sure there is no dry flour in the mixture. Cover the bowl with a clean dry towel and let it stand for 30 minutes.
Stretch and fold the dough. Uncover and grab one side of the dough and lift it just above the lip of the bowl folding it over the other side. Turn the bowl 90 degrees and stretch and fold the dough again. Repeat this process 4 times then re-cover the bowl.
Repeat the stretching and folding process every 30 minutes for 4-6 hours. The dough will rise very slowly during this process. Unlike traditional yeast dough, sourdough will only rise about 50%-70%. (The ambient temperature will affect how quickly the dough rises. The warmer the location the more quickly it will increase in volume.)
Once the dough has risen, turn it out onto a lightly floured surface. Shape the dough into a soft ball and let it stand on the counter for 20 minutes to rest.
Sprinkle the inside of a clean mixing bowl with flour. Place the dough inside and put in the fridge for 24 hours to cold proof.
After the 24 hours, preheat the oven to 450°F. Place the covered dutch oven into the oven while it preheats.
Remove the dough from the fridge and turn the dough it out onto a piece of parchment paper. Smooth and shape into a ball and score the top with a sharp knife about 1/4 of an inch deep and a couple of inches across.
Pick up the dough by the parchment edges and carefully place inside the hot dutch oven. Lower the oven temperature to 425°F. Cover and bake for 30 minutes.
After 30 minutes remove the lid off the dutch oven and bake for another 10-15 minutes until golden.
Remove the bread from the dutch oven using the parchment paper and let stand for 20-30 minutes, then slice and serve.