In a large bowl, combine the mature sourdough starter and lukewarm water. Stir to combine, then gradually add the all-purpose flour and salt. Mix until no dry flour remains.

Let the dough rest for 30 minutes to allow gluten to develop.

After resting, knead the dough on a floured surface for about 10 minutes until it becomes smooth and elastic.

Place the dough in a lightly oiled bowl, cover it, and let it rise for about 3 hours or until doubled in size. Gently fold the dough every hour to strengthen it.

Once risen, turn the dough onto a floured surface and gently deflate it. Shape it into a round or oval loaf.

Place the shaped loaf onto a floured banneton for another 1-2 hours or until puffed.

Preheat your oven to 450°F (232°C) and place a Dutch oven or baking stone inside.

Carefully transfer the loaf onto parchment paper. Score the top with a sharp knife and place it in the hot Dutch oven, cover, and bake for 30 minutes. Remove the cover and bake for an additional 15-20 minutes until golden brown.

Let the bread cool on a wire rack for at least 30 minutes before slicing.