Prepare Chia Seeds – In a small bowl, soak chia seeds in 25g of hot water. Stir and let them absorb the water for about 10-15 minutes until they form a gel-like consistency.
In a large bowl, mix 350g of all-purpose flour, 240g water, and 40g of active sourdough starter.
Add the soaked chia seeds and salt then, mix until just combined.
Cover and let it rest for 30 minutes.
Perform 4 sets of stretch and folds every 30 minutes to build strength.
Cover the bowl and let the dough ferment at room temperature (21-24°C) for 4-6 hours
Shape the dough into a ball, and place it in a floured proofing basket or bowl.
Cover and refrigerate overnight (8-12 hours) for a cold proof.
Preheat oven to 250°C with a Dutch oven inside.
Place the dough onto parchment paper, score the top, and bake covered for 25 minutes.
Remove the lid and bake for another 15 minutes or until golden brown.
Let the bread cool completely before slicing.