In a large mixing bowl, combine the bread flour and water. Mix until there are no dry bits of flour. Let the mixture rest for 30 minutes (this is called autolyse).
After the resting period, add the sourdough starter and salt to the dough. Mix well until fully incorporated.
Cover the bowl with a damp cloth or plastic wrap and let it rest at room temperature for about 4-6 hours. During this time, stretch and fold the dough every 30 minutes for the first 2 hours.
Once the dough has doubled in size, gently remove it from the bowl onto a floured surface. Shape it into a round or oval loaf, depending on your preference.
Place the shaped dough into a proofing basket lined with flour. Cover it and let it rest for another 2-4 hours at room temperature or overnight in the fridge for a slower fermentation.
About 30-45 minutes before baking, preheat your oven to 450°F (230°C) with the Dutch oven inside.
Once the oven is hot, carefully remove the Dutch oven. Transfer the dough to a piece of parchment paper and score the top with a lame or sharp knife.
Using the parchment paper, lift the dough into the hot Dutch oven. Cover it with the lid and bake for 30 minutes. Remove the lid and bake for an additional 10-15 minutes until the crust is golden brown.
Once baked, remove the bread from the Dutch oven and let it cool on a wire rack for at least 1 hour before slicing.