STEP 1: BUILD THE LEAVEN (DO THIS ABOUT 12 HOURS BEFORE MIXING DOUGH):

• In a bowl, mix 100g of 90F water with 25g ripe sourdough starter.
• Add 100g bread flour to the mixture and stir until well combined and no lumps remain.
• Cover the bowl and let it sit at room temperature for 12-14 hours. The leaven should become frothy, bubbly, and increase in size.

STEP 2: MIX THE DOUGH:

• In a mixing bowl, combine 275g 92F water with all of the ripe leaven. Stir until the leaven is dissolved in the water.
  
• Add 400g bread flour, 50g whole wheat flour, and 12g salt to the mixture.
• Use a sturdy spoon to mix the ingredients until a dry clump forms. Then, wet your hand and use it to squeeze and fold the dough until it is homogeneous and there are no dry spots.

STEP 3: BULK FERMENTATION:

• First Rest: Cover the bowl and let the dough rest for 30 minutes.
• First Fold: After 30 minutes, grab a portion of the dough, stretch it until you feel resistance, then fold it over itself. Repeat 5-6 times, then flip the dough and round it into a ball. Cover and let rest (a second time) for another 30 minutes.
  
• Second Fold/Final Ferment: Repeat the folding process one more time after the second 30-minute rest. After this, cover the dough and place it in a warm spot (about 90-95°F/35C) to ferment for 2 more hours.

STEP 4: SHAPING DOUGH:

• Lightly flour a cutting board and flip the dough out onto the floured surface. Grab opposite sides of the dough, pull them out, and fold over each other. Rotate the dough and repeat a total of at least 4 times.
• Flip the dough over onto the folds and round it while stretching the top down and under to create tension.
  
• If using a proofing basket, dust it with flour. If using a bowl, line it with a tea towel (kitchen towel) and dust with flour.
• Place the shaped dough seam side up in the basket. Give it a few more pull out and folds as shown in the video to create added tension.

STEP 5: PROOFING:

• Cover and let proof in a warm place for 60-90 minutes.
• After 60-90 minutes, the dough should have increased in size by about 60%. To test, gently poke the dough; if it slowly bounces back, it is ready to bake. Judge proofing by the way the dough looks, reacts to the poke not the time. Proofing in a cool room will take much longer than in a warm room.

STEP 6: BAKING:

OPTION 1: BAKING ON A SHEET TRAY:

• Preheat Oven: Preheat your oven to 450°F/232C
• Prepare for Baking: Flip the dough onto a parchment-lined sheet tray.
• Score the Dough: Use scissors to make 5-6 overlapping snips on the top of the dough.
• Create Steam: Spray the dough 6-10 times with water and cover with a foil pan lid.
• Initial Bake: Bake covered for 15 minutes.
• Final bake: Uncover and Continue Baking: Remove the foil lid, add a wire rack to baking sheet, and bake for an additional 30 minutes.

OPTION 2: BAKING IN A DUTCH OVEN:

• Preheat your Dutch oven in a 475°F/245C oven.
• Carefully flip the proofed dough onto a piece of parchment paper sprinkled with semolina flour.
• Use scissors to make 5-6 angled snips on the dough.
• Initial bake: Place the dough and parchment paper into the preheated Dutch oven, cover with the lid, and bake for 15 minutes.
  
• Final bake: Remove the lid and bake for an additional 20-25 minutes.