In a large bowl, add the sourdough starter, water and olive oil. Mix with a fork to combine, then add the flour and salt. Continue mixing until the dough becomes stiff, then squish it together with your hands to incorporate all the flour. The dough will be rough and shaggy.

Cover the bowl with plastic wrap, reusable wrap, or very damp kitchen towel. Let rest (autolyse) for 30 minutes to 1 hour.

After resting, return to the bowl and work the dough into a rough ball, about 15 seconds.

Cover the bowl with lightly oiled plastic wrap. Alternatively, transfer the dough to a high-sided dough tub. Let it rise in a warm place, ideally 70-75 F. The dough is ready when it no longer looks dense and has almost doubled in size.

During the bulk fermentation, you can do a series of ‘stretch & folds’ to strengthen the dough. Start 30-45 minutes in: lift a portion of the dough, stretch it upwards, and fold it over itself. Rotate the bowl ¼ turn and repeat until you’ve come full circle (1 set). Do 1-2 additional sets, spaced ~1 hour apart.

Remove the dough onto a lightly floured surface. Starting at the top, fold the dough over toward the center. Turn slightly, and then fold over the next section. Repeat until you have come full circle. Flip the dough over, seam side down. Gently cup the sides and rotate in a circular motion to tighten the shape.

If you’ve used 250g water, you can do a free-form second rise in the Dutch oven. Line the pot with a piece of parchment paper or coat with cornmeal. Place the dough inside, cover and let rise for about 30 minutes to 1 hour. Preheat your oven to 450 F/ 232 C.

Right before baking, make a shallow 2-3 inch slash in the center of the dough using a bread lame, razor blade, or small sharp knife.

Place the bread in the oven on the center rack (lid on) and reduce the temperature to 400 F/ 204 C. Bake for 20 minutes, then remove the lid, and continue to bake (uncovered) for another 40 minutes, until deep, golden brown.

Remove the bread from the hot Dutch oven, and cool on a wire rack for at least an hour before slicing.