Mix 500 g flour with 350 g water
Add 100 g active sourdough starter
Add 10 g salt
Stir until no dry flour remains
Cover and rest 30 minutes
Stretch and fold the dough
Repeat stretch and fold 3 times at 30-minute intervals
Let the dough rise until doubled
Shape the dough into a loaf
Place in a proofing basket or bowl
Cover and proof until puffy
Preheat the oven to 230°C
Score the dough
Bake with steam for 20 minutes
Remove steam and bake 20 to 25 minutes more
Cool completely before slicing