Feed your starter until it's active (until it has doubled in size ~12h at 20°C)
Mix flour, sourdough and the active starter and let rest for 30-60 minutes
Add salt and bassinage water (start with less reserve water if unsure)
Knead the dough for 3-5 minutes
Let rest for 30 minutes and do 3 sets of stretch and fold in 30 minute intervals over 1.5h
Cover and let rest for 2.5-3h at 20°C room temperature (adjust time if room is warmer)
Pre-shape the dough and let rest for 20 minutes
Final shape, place in banneton, cover and chill in fridge for 12-36h at 5°C
Preheat the oven with a pizza stone or bread baking pan to 230-250°C for 1h
Score the bread dough with a blade at a ~45° angle
Bake for a total of 45 minutes (20 minutes with steam and 25 minutes without)
