To begin, combine 1 cup (120g) of all-purpose flour with ½ cup (120g) of warm water in a large glass jar, stirring until well combined, then cover and let it rest at room temperature.

On day two, discard half of the starter and feed the remainder with 1 cup of flour and ½ cup of water, mixing thoroughly before covering it again.

Repeat the feeding process daily for the next five days, ensuring to discard half of the starter each time before adding fresh flour and water.

By day seven, your starter should be active and bubbly, indicating it's ready for baking; perform a float test to confirm its readiness.

In a large bowl, mix 100g of mature sourdough starter with 300g of bread flour, 200g of water, and 7g of salt until a shaggy dough forms, then cover and let it rest for 30 minutes.

Perform a series of stretch and folds every 30 minutes for 2 hours, then let the dough bulk ferment at room temperature until it has doubled in size.

Gently shape the dough into a round or oval, place it in a proofing basket, and refrigerate overnight for a slow fermentation.

Preheat your oven to 450°F (230°C) with a Dutch oven inside for at least 30 minutes.

Carefully transfer the dough to the hot Dutch oven, score the top, and bake with the lid on for 30 minutes, then remove the lid and bake for another 20-25 minutes until golden brown.