Add the active sourdough starter and lukewarm water to a large mixing bowl. Stir until the starter is mostly dissolved and the water looks cloudy.

Add the bread flour and salt. Mix until all the flour is hydrated and no large dry patches remain. The dough will look rough and shaggy.

Cover the bowl and let the dough rest for 30 minutes.

Wet one hand lightly. Stretch one side of the dough upward and fold it over the center. Rotate the bowl and repeat on all four sides.

Cover the dough and rest for 30 minutes. Repeat the stretch-and-fold process two more times, resting for 30 minutes between each set.

Cover the bowl and allow the dough to bulk ferment at room temperature. The complete bulk fermentation will usually take approximately 4 to 7 hours from the time the dough was mixed.

Continue fermentation until the dough has increased by approximately 50 to 75 percent. It should look smoother, slightly domed, bubbly, and airy.

Turn the dough onto a lightly floured work surface. Gently fold the sides toward the center and shape the dough into a round loaf.

Create light surface tension by gently pulling the dough toward you several times. Avoid pressing out all the air.

Place the shaped dough seam-side down on a sheet of parchment paper.

Cover the dough with an inverted bowl or clean kitchen towel. Let it rest at room temperature for 45 to 75 minutes.

Use a sharp bread lame, razor, or knife to make one confident cut approximately ½ inch deep across the top.

Use the parchment paper to lower the dough into a completely cold Dutch oven. Place the lid on the pot.

Put the covered Dutch oven into a cold oven. Set the oven temperature to 450°F and begin timing immediately.

Bake covered for approximately 50 minutes.

Carefully remove the lid and bake uncovered for another 15 to 20 minutes, or until the crust is deeply golden brown.

Remove the loaf from the Dutch oven and transfer it to a cooling rack.

Cool for at least 2 hours before slicing so the interior crumb can finish setting.