1Feed your starter: mix 50g starter, 50g unbleached bread flour and 50g filtered water.
2Let your starter rise overnight or for 6-8 hours until doubled in size and starting to fall.
3In a bowl, mix 100g active starter and 350g of filtered water until you get a milky consistency.
4Add 500g of unbleached bread flour and 10g of salt; mix the dough until there are no more dry flour clumps.
5Cover the dough and let it rest for one hour.
6Perform four rounds of stretch and folds, spacing 30 minutes apart. Wet your hands and gently reach under the dough, pulling it up and folding it into the middle. Repeat for all four sides. Do not tear the dough.
7Let the dough rest for another 3-4 hours for bulk fermentation. Dough is ready when it's almost doubled in size, jiggly, airy, and bubbly.
8Prepare your banneton basket or a bowl with a towel.
9Shape the dough: gently flip the dough onto the surface. Stretch it into a rectangle. Fold the right side into the middle, then the left side on top. Roll the dough up tightly from the bottom, tucking in the edges. Shape into a ball by using a push-turn-pull-turn movement (repeat 8-10 times).
10Cover the dough and let it rest for 30 minutes.
11Place the dough into the prepared banneton basket (seam-side down). If dough is trying to split, use stitching: grab an edge and pull it towards the middle.
12Refrigerate overnight (14-24hrs) or do a second rise at room temperature for 2 hours.
13Preheat oven with the dutch oven inside at 450 degrees.
14Flip your dough onto parchment paper. Sprinkle rice flour on top (optional). Use a bread lame to score the dough (decorative scoring first, then expansion score).
15Bake at 450 degrees for 30 minutes covered, then 15 minutes uncovered.
16Remove the bread from the dutch oven and let it cool for 1-2 hours on a wire cooling rack before cutting.