In a large bowl, combine the active starter and warm water until mostly dissolved.
Add the flour and mix (using your hands) until no dry flour remains. Cover with a damp tea towel (or disposable shower cap) and let rest for 45 minutes.
Add the salt and work it into the dough with your hands until evenly distributed.
Perform the first set of stretch and folds in your bowl. Cover and rest for 30 minutes.
Perform a second set of stretch and folds in your bowl. Cover and rest for 30 minutes.
Perform a third set of stretch and folds in your bowl. Cover and allow the dough to continue rising until puffy and nearly doubled in size. (1-5 hours)
Turn the dough onto a lightly floured surface.Fold the edges of the dough toward the center about 4-5 times, working your way around the loaf.Next, gently stretch the dough into a rectangle. Fold it over on itself hot-dog style, then roll it up longways.Finally, use your hands to pull the dough toward yourself across the counter a few times. This creates tension on the outside of the loaf and helps give you that beautiful oven spring when it bakes. Let rest under damp tea towl for 20 minutes. Perform a final shaping and place seam-side up in a floured banneton or towel-lined bowl.
Cover and refrigerate overnight.
The next morning, preheat a Dutch oven to 475°F for 25–30 minutes.
Turn the dough onto parchment paper, score the top, and carefully transfer it to the hot Dutch oven.
Bake covered for 25 minutes.
Reduce oven temperature to 450°F, remove the lid, and bake another 15–20 minutes until deep golden brown.
Allow the loaf to cool for at least 1 hour before slicing.