In a the bowl of a stand mixer combine the starter, water, olive oil, and bread flour. Mix with your hands until it comes together in a shaggy mass. Let it rest for 30 minutes.

Attach the dough hook to the mixer and begin kneading the dough on low speed. Add in the salt. Increase the speed to medium and knead for about 5 minutes, or until the dough is smooth and soft.

Place the dough in a lightly oiled bowl. Cover the bowl with plastic wrap and a clean kitchen towel. Let it rise in a warm place until doubled in volume. In a warm climate, this will take about 3 hours. In a cold climate, this can take up to 12 hours. You can let the dough rise overnight in the fridge.

Remove the dough from the bowl and place on a lightly floured work surface. Cut the dough in half to make 2 smaller loaves. Cover and store the extra dough in the fridge or freezer until ready to bake.

Gather the dough, one side at a time, and fold it over into the bottom center. Place the dough seam side down. Use your palms to roll it around into a tight ball. Coat the bottom of a Dutch oven with cornmeal and place the dough inside. Cover and let rise again for 1 to 2 hours, or until puffy.

Meanwhile, preheat the oven to 450°F. Use a very sharp knife to make a 2-inch long shallow slash in the center of the dough.

Cover the dough with the Dutch oven lid and place in the oven. Reduce the temperature to 400°F and bake for 20 minutes. Remove the lid and continue to bake uncovered for an additional 40 minutes, or until very golden brown. During the last minute or baking, crack the oven door open just enough to allow moisture to escape for a crisper crust. The sourdough is done when the internal temperature reaches about 205°F.

Remove the bread from the oven and let cool on a wire rack for an hour before slicing and serving.