Bring starter to temp of 25° (remove from refrigerator, feed and place inside of your oven, turned OFF, but with the light on 24 hours before use)
MORNING: Reserve 50g of warm water for later. Combine the remaining water with the flour and let sit for 1 hour in a warm place.
Add salt, reserved water, and levain to your already mixed flour & water and mix thoroughly
Dough temp should be above 25°. Stretch/fold/knead 3x in 30 min intervals.
Cover dough and let sit at a warm temp for 2-3 hours
Lightly flour work surface and dump out dough. Divide the dough into two halves. Lightly flour your other hand and using both a kitchen scraper (optional) and your hand turn each half of dough on the counter while lightly pulling the dough towards you. (forming a round circle). Let the dough rest for 25 minutes, uncovered.
Shape and transfer to banneton with seam side facing up. Cover with plastic to keep moisture in and seal with an elastic band. Refrigerate overnight.
Put your Dutch Oven or Pyrex bowl with lid inside oven and begin preheat for 1/2 hour at 450°
Place on parchment paper and score (cut a pattern)
Mist lightly with water. Place in hot Dutch oven with the lid on for 20 minutes
Remove lid and bake for 30 mins uncovered/until internal temperature registers over 208°F.
Let cool on a wire rack