Combine starter and water; add dry ingredients. Combine first with a fork or a dough whisk and then by hand or by using a dough scraper into a shaggy dough.
Autolyse (let rest) for one hour, stretch and fold for two rotations (4 x around the bowl twice) to make a more smooth dough.
Bulk ferment dough on your counter in a loosely covered bowl until doubled in size. The timing will depend on the temperature of where you proof your dough. For me in the Summer months, it takes about 4-6 hours, in the Winter it can take up to 12 hours (all day or overnight).
Transfer your covered dough to the refrigerator and cold proof for 12-48 hours.
When ready to bake, remove dough to a floured board and shape into a rough rectangle. Cut the dough in half lengthwise and then each piece in half and then in half again. This will give you 8 fairly equal pieces. Use flour as needed to keep dough from sticking.
Transfer dough onto a lined or liberally floured sheet pan and bake now or cover the pan with a towel and let rest for one hour before baking. This extra step will give your ciabatta a bit more rise.
Preheat oven to 475ºF. Bake on middle rack for 10 minutes; reduce heat to 450ºF, rotate pan, and bake for 10-15 more minutes.
Let cool for 20-30 minutes before cutting. Enjoy!
