Take the unfed starter in a small transparent jar and add 14 gms each of all purpose flour and water. Set aside for 3-4 hours till it doubles in size
Mix the 225gms flour and 135 gms water for the dough in a mixing bowl. Set aside for 3-4 hours till the starter is ready
Add the starter and 8 gms salt to the mixing bowl with the flour and water. Mix well to incorporate the starter and salt and form a shaggy dough
After 30 minutes, stretch one side of the dough and place it on the middle of the dough. Repeat the same stretch and fold on 4 sides of the dough like an envelope.
Do 3 more such stretch and folds at 30 minute intervals totally taking 2 hours.
Cover the dough with a cloth or lid and set aside for 3-4 hours till it rises significantly in volume
Once the dough has risen, carefully transfer it to a lightly floured surface. Perform one more round of stretch and fold and form the dough into a tight ball.
Transfer the dough ball to a banetton or any lightly floured bowl. Cover it with cling wrap or a ziploc and refrigerate it for 10 hours
Preheat the oven to 250C and grease a dutch oven or baking tray
Transfer the dough to the dutch oven and use a blade or sharp knife to make some cuts to the top of the dough. This allows the steam to escape from the loaf while baking
Cover and bake for 30 minutes. Bake uncovered for 25-30 minutes till the top is a nice golden brown
Cool the loaf completely on a cooling rack for 1-2 hours. Slice only after the loaf is fully cooled