The night before:10:00 PM - Feed your sourdough starter, but only use 5 g of your original starter, then add 50 g flour blend, 50 g water. Mix, mark with a rubber band on the outside, and let mature in a warm place for 12 hours. It should be at young levain stage by 10 AM.

The next morning:10:00 AM - Your starter should be at least doubled at this point. In a large bowl, add 100 grams (nearly the entire jar) of the starter and mix with 375 g water. Use whatever is left in your jar to feed your normal starter 1:4:4 feed (I do 5 g starter, 20 g flour blend, 20 g water).

Add the remaining flours and combine well with starter water. Scrape down the sides of the bowl and gather into a shaggy mass in the middle. Cover and let sit in a warm spot in your kitchen for 1 hour (this acts as a quasi-autolyse).

11:00 AM - Add 10 g salt and use wet hands to mix in, this should take about 3 minutes to completely mix in the salt. Cover and let rest for 30 min in a warm place.

11:30 AM - Do one set of stretch and folds: With wet hands, scoop your hand under one side of the dough, gently pull it up until just before it looks like it'll resist and tear (about 4-6 inches), then fold it over the center. Turn 90 degrees, and repeat the movement, and repeat this stretch and fold until you've done all 4 sides. Cover and let sit for 30 min.

12:00 PM - Perform another set of stretch and folds. Cover and let sit for 30 min.

12:30 PM - Perform another set of stretch and folds. Cover and let sit for 30 min.

1:00 PM - Perform a final set of stretch and folds, then cover let sit for 1 hour.

2:00 PM - At this point, I check to see if the dough is poofy enough (it should have risen about 60% from the original amount). It's kind of hard to tell, but eventually you'll see the dough feel bouncy and kind of alive. It won't have completely relaxed into a puddle like it did around 12 PM. I usually perform another stretch and fold and let sit for another half hour since it's winter where I am, but use your judgement.

Approx 3:00 PM - Now you preshape - Lightly flour your surface and flip your dish overtop, allowing the dough to slowly release itself from its vessel. Perform a gentle envelope fold (top, side, side, bottom), then use a bench scraper to flip the dough, seam side down.

Gently shape into a ball by pushing the bench scraper in a backwards C motion and pull the dough towards you. You'll gently rotate the dough with this motion a few times to create a bit of surface tension in the dough. Let rest for 15 minutes.

While your dough rests, prep your proofing container. If you have a banneton, use white rice flour to dust the inside so it won't stick to your dough. If you don't have a banneton, you can use a loaf pan lined with a lint-free tea towel, dusted well with rice flour. Regular flour will not be as effective as rice flour, I highly recommend rice flour. Set aside.

~15 min after preshape3:15 PM - Final shape (this is for an oval loaf, called a batard)

Use your bench scraper to scoop under the dough and flip onto a lightly floured surface. With lightly floured fingers, gently fold the top over into the middle, and tap lightly to seal. Gently pull the bottom to fold over the folded top, to create a long log shape. Tap lightly to seal.

Turn 90 degrees, then tuck your thumbs into the top 2 inches of the dough, and use the rest of your fingers to tuck and rough the down gently and firmly towards you (like a sleeping bag).

With seams down, close the two short ends by pinching the edges together. Then, use your bench scraper to gently push the dough and tuck the seams underneath to try to create surface tension. Use the bench scraper to scoop the dough into your hands (or flip over), then place the dough into your rice-floured banneton or loaf pan, seams up.

You can lightly "stitch" the dough if you find it kind of unraveled (pulling the dough over each other left to right in a zig-zag pattern). Dust extra rice flour along the edges.

At this point, check the proof by doing a poke-test: poke a floured part of the dough around the edge and it should spring back but leave a slight dent.

If it springs back and doesn't leave a dent, let it sit, covered with a plastic bag or clean shower cap (avoid letting it touch the top) for another 15-20 minutes until it springs back. Careful not to let it overproof: when it's overproofed, it doesn't spring back at all and just stays dented if you poke it. Let sit on the counter if it's not yet springy.

3:30 PM - Place your covered and proofed bread loaf in the fridge to cold-proof until you bake the next morning.

The BakeAnytime the next day between 3 AM and 3 PM - Preheat your Dutch oven (or cast iron pan) in the oven at 500F (260C). Allow to preheat for at least 30 minutes.

Pull your dough out of the fridge, and flip onto a piece of parchment paper. Score the top of your dough about 1/2 inch to 3/4 inch deep.

Transfer to your preheated cast iron Dutch oven, cover with lid. I like to add a splash of water or an ice cube inside the Dutch oven just as I'm about to close the lid. You don't need to do this though. The extra steam gives it more flexibility to expand.

Bake for 20 minutes. After 20 mins, lower the heat to 450F (230 C), and remove the lid of your Dutch oven. Continue to bake for another 20 minutes, or until you get a
nice, deep brown crust. After you reached your desired brownness, pull out of the oven and take the bread out to cool directly on a wire rack.

Let cool for at least 2-3 hours before cutting into your bread. Once cooled completely, store in a bread bag for up to a week. Enjoy!