1. Combine and Autolyse: In a large mixing bowl, gently mix the active sourdough starter, warm water, and salt until mostly combined. Add the bread flour and mix with your hands or a sturdy spoon until no dry flour remains. The dough will be shaggy. Cover the bowl with a damp cloth or plastic wrap and let it rest for 30 minutes. This resting period, called autolyse, allows the flour to fully hydrate.

2. Incorporate Dates and First Fold: After the autolyse, sprinkle the chopped dates evenly over the dough. Perform your first set of stretch and folds. To do this, wet your hands slightly, grab a portion of the dough from one side, stretch it upwards, and fold it over to the opposite side of the bowl. Rotate the bowl a quarter turn and repeat this process 3-4 more times, ensuring the dates are gradually incorporated. Cover and let rest for 30 minutes.

3. Perform Subsequent Folds: Over the next 2-3 hours, perform 3-4 more sets of stretch and folds, spaced 30-45 minutes apart. Each time, gently stretch and fold the dough over itself 4-6 times. This builds strength in the dough and helps distribute the dates evenly. By the last fold, the dough should feel more elastic and cohesive.

4. Bulk Fermentation: After the final fold, cover the bowl and let the dough bulk ferment at room temperature (around 72-78 F / 22-25 C) for 3-5 hours, or until it has increased in volume by about 30-50% and looks bubbly. The exact time will depend on your starter’s activity and room temperature.

5. Pre-Shape and Bench Rest: Lightly flour your work surface. Gently turn the dough out onto the floured surface. Using a bench scraper, gently shape the dough into a loose round or rectangle. Avoid deflating it too much. Cover with a damp cloth and let it rest for 20-30 minutes. This is the bench rest, which allows the dough to relax before final shaping.

6. Final Shape and Cold Proof: Lightly flour your banneton (proofing basket) or a bowl lined with a floured kitchen towel. Gently shape the dough into your desired final shape (batard or boule). Place the shaped dough seam-side up into the prepared banneton. Cover with plastic wrap or a shower cap and refrigerate for 8-12 hours, or up to 24 hours. This cold proofing develops flavor and makes the dough easier to handle.

7. Bake the Bread: Preheat your oven to 450 F (232 C) with your Dutch oven inside for at least 30-45 minutes. Carefully remove the hot Dutch oven. Gently invert the cold dough into the hot Dutch oven. Score the top of the dough with a sharp razor blade or knife. Cover with the lid and bake for 30 minutes.

8. Finish Baking: Remove the lid from the Dutch oven and continue baking for another 15-20 minutes, or until the crust is deeply golden brown and the internal temperature reaches 200-210 F (93-99 C). Carefully remove the bread from the Dutch oven and transfer it to a wire rack to cool completely for at least 1-2 hours before slicing.