In a mixing bowl, combine flour and water. Mix until no dry flour remains. Cover and let the mixture rest for 30 minutes.
After 30 minutes, add the active sourdough starter and salt to the dough. Mix well by hand, pinching and folding until fully incorporated.
Transfer the dough to a lightly floured surface and knead for 5-7 minutes until it becomes smooth and elastic.
Place the kneaded dough in a clean bowl, cover with a kitchen towel, and let it ferment at room temperature for about 4-6 hours, performing stretch and folds every 30 minutes for the first 2 hours.
Lightly flour your work surface and shape the dough into a round loaf. Cover and let it rest for about 30 minutes.
Shape the dough into a batard or loaf shape and place it in a proofing basket or bowl, seam side up. Cover and let it proof for another 2-4 hours at room temperature or in the refrigerator overnight.
If proofing in the refrigerator, remove the dough and let it warm up for about 30 minutes before baking. Preheat your oven to 475°F (245°C).
Carefully transfer your dough onto a baking sheet lined with parchment paper or a pizza stone. Score the top of the loaf with a sharp knife.
Bake in the preheated oven for about 30 minutes until the bread is golden brown and sounds hollow when tapped.
Allow the bread to cool on a wire rack for at least an hour before slicing.