Sourdough bread

Levain (8:00 am): In a small container, mix the levain ingredients and keep at 80°F for 5 to 6 hours.
Autolyse (12:00 pm): In a medium mixing bowl, mix the flour and 603 grams of 74°F water (reserve 50 grams until the next step). Cover and let rest for 1 hour.
Mix (1:00 pm): To the mixing bowl holding your dough, add the salt, ripe levain (from step 1), and reserved 50 grams water. Mix by hand or with a dough whisk until incorporated. Transfer your dough to a bulk fermentation container and cover.
Bulk fermentation (1:15 pm - 6:30-ish): Give the dough 5 sets of stretch and folds at 30-minute intervals, where the first set starts 30 minutes after the start of bulk fermentation.
Divide and preshape (6:30 pm): Lightly flour your work surface and scrape out your dough. Using your bench knife, divide the dough in half. Lightly shape each half into a round shape. Let the dough rest for 25 minutes, uncovered.
Shape (7:00 pm): Shape the dough into a round (boule) or oval (batard). Place in proofing baskets.
Rest and proof: Cover proofing baskets with reusable plastic and seal shut. Let the dough sit out on the counter for 20 minutes. Then, place both baskets into the refrigerator and proof for a day (if you are making the dough on Tuesday, you'll bake Thursday morning).
Bake (Preheat oven at 8:30 am, bake at 9:30 am): Preheat your oven with a combo cooker or Dutch oven inside to 450°F. When the oven is preheated, remove your dough from the fridge, score it, and transfer to the preheated combo cooker. Add two ice cubes to create steam. Place the cooker in the oven, cover with the lid, and bake for 30 minutes. After this time, remove the lid (you can keep it in the oven or remove it) and continue to bake for 15-20 minutes longer. When done, the internal temperature should be around 208°F (97°C). Let the loaves cool for 1 to 2 hours on a wire rack before slicing.