Before starting your dough, take your mature starter and feed it with the bread flour and water.

Let rise 6-8 hours at 75°F/24°C until doubled.

In a large mixing bowl, combine all ingredients until fully mixed.

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

Do a set of stretch and folds. Gently stretch and fold the dough, lifting one side, stretching it up, and folding it over the center. Rotate the bowl and repeat on each side until you have done all four "sides".

Recover the bowl.

Perform 4-5 sets of stretch and folds over the next 2-3 hours, about evert 30-45 minutes.

Cover the bowl with a damp towel or plastic wrap.

Let the dough rise in a warm place for 3-4 hours, until it has noticeably expanded.

Turn the dough onto a lightly floured surface.

Use a bench scraper to divide the dough in half and shape each portion into a round (boule) or oval loaf.

Place each shaped dough, seam side up, into a floured banneton basket or bowl lined with a clean towel.

For the final rise, cover the bread dough with plastic wrap or a damp towel and let it proof for 1-2 hours, until slightly puffed. Alternatively: cover and refrigerate overnight. If refrigerated, be sure to score and then bake it straight from the fridge.

Preheat by setting your oven temperature to 450°F (230°C). Place the Dutch oven with its lid on in the oven to preheat for at least 30 minutes.

Carefully turn the dough onto a piece of parchment paper.

Score the top with a sharp knife or bread lame to allow steam to escape while baking.

Transfer the dough (on parchment paper) into the preheated Dutch oven.

Cover and bake for 20 minutes.

Remove the lid and bake for an additional 20-25 minutes, until your sourdough loaf is golden brown and sounds hollow when tapped.

Repeat this process with second loaf.

Transfer the baked loaves to a wire rack. Let them cool completely for at least 1 hour before slicing to help set the crumb.