Combine water and starter in a bowl and mix with Danish whisk if you have one, if not a wooden spoon will work. Add bread flour and salt and mix to form a shaggy dough.
Perform 4 sets of stretch and folds every 30 minutes for 2 hours. This will build gluten in dough.
Shape dough and put in banneton basket, cover, and refrigerate over night (or for two days if you have time to build more flavor)
Preheat oven to 450℉. Place dough on parchment paper, score loaf about ¼ deep and put in one of the steel bread pans, add one ice cup. Cover with other steel bread pan. Bake 40 minutes. Remove lid and bake for another 10 minutes.
