You'll need to get some "starter" from a friend!
Feed your starter once a week and keep it in the fridge until the day you want to use it. After you use the required amount of starter, there will be "discard." Don't put this down the drain. Either use it in a recipe calling for "sourdough discard" OR put it in the garbage.
Feeding your starter:
20 g lukewarm water
5-7 g mature starter
20 g bread flour
Mix well in a small jar. Scrape down the sides. Cap loosley. Allow to double at room temperature. (Repeat the process two more times if your starter has been in the fridge for a week.) When it is healthy and mature, it should look bubbly and airy.
Using a vigorous and healthy starter is crucial in the next step.
Mixing the levain:
100 g lukewarm water
25 g mature starter
100 g bread flour
Mix well in a quart jar. Scrape down the sides. Cap loosely. Allow to double at room temperature. (Place a rubber band around the jar at the level you want it to be when it is doubled...then you can see when it is ready.)
When it is ready, put 10+ g of the levain in a small jar and use it as your "starter" for the next time: Cap it loosely and put it in the fridge!
Next, mix together:
578 g lukewarm water
859 g bread flour
160 g levain
Using a heavy spoon in a big bowl (or a stand mixer), mix until there are no dry pockets of flour. Sprinkle 19 g fine sea salt on top. Cover and let it sit for 30-40 min. at room temp.
After letting the dough sit for 30-40 min, use a dough hook in a stand mixer and set the mixer on low and let it run for 3-5 min.
Stretching and folding the dough helps develop the gluten. Starting at one end of the dough, pull it up and then fold it over the top of the dough. Rotate the dough and do this again on each of the 4 sides...stretch it up, fold it over, and rotate. Flip the dough over so the seam side is down. Place the kneaded dough in a large, lightly oiled container (big enough that the dough can double in size). Cover it and let it rest for 15-20 min until the top of the dough is relaxed and smooths out.
Repeat the stretching and folding step (on 4 sides). Cover and let it sit 15-20 min.
Then do that again...stretch and fold on all sides. Cover with a light towel AND plastic, and let it sit 4-6 hours after the last fold...until the dough doubles in size. You should get some nice big bubbles on the surface. (Don't do this overnight. If you need to let it sit overnight, put it in the fridge and then let it come to room temp and double the next day.)
After the dough has doubled, gently dump it out on the counter. Using a bench scraper, divide the dough in half. Handle it very carefully. Gently pull and fold one end over the middle. Roll the rest of the dough to the side so the seam is down. Gently roll and rotate the dough until the surface is nice and tight.
Work some bread flour into a light towel. Place the towel in the bottom of a bowl. This is your "proving basket." Gently place the dough into the bowl with the towel seam-side UP. Pinch the seam together to seal. Cover the basket or bowl with a light towel AND plastic and place it in the fridge for 12-15 hours...great to do overnight!
When you are ready to bake, put some dry rice and a little rack in the bottom of your Dutch Oven baking roaster (this keeps the bottom of the loaf from burning). Put the covered Dutch Oven pan in a cold oven and turn the temperature to 475 degrees. Let the oven heat and sit at this temp for an additional 15 min. Place a baking stone on the rack directly below the Dutch oven. (This also will keep the bottom of the loaf from burning.) Once the oven has heated, take one of the proving baskets/bowls out of the fridge. Place a piece of parchment on your counter. Carefully turn out the dough onto the parchment. Using a bread lame or very sharp razor blade, score the top of the loaf lightly in several small cuts (this is where you can create a pretty design).
Open your hot oven, carefully take the hot lid off of the heated Dutch oven and carefully lower the parchment and dough down into the hot pan. Replace the lid and bake for 35 min. Remove the lid. If the bread is still a light tan color, bake it an additional 5 minutes uncovered until it is a deep golden brown.
Gently lift out the parchment and allow the loaf to cool for 45 min before slicing. Let the oven and the pan heat up again, and then use the hot Dutch oven to bake the other loaf in the same way.
