Instructions

• In the bowl of a stand mixer fitted with a dough hook, add 150 g active sourdough starter, 300 g warm filtered water (about 90°F), 450 g flour (300 g bread flour + 150 g all-purpose), and 12 g salt. Mix on low speed until the ingredients come together, then increase to medium-low and mix for about 5 minutes, until the dough is cohesive and slightly elastic. Stop the mixer, cover the bowl, and let the dough rest for 15 minutes.
• After the 15-minute rest, wet your hands and perform a set of stretch-and-folds: reach under one side of the dough, stretch it up and fold it over the top; repeat for all four “sides” of the dough. Cover the bowl and wait 15 minutes.
• Repeat the stretch-and-fold set one more time (wet hands, stretch and fold each of the four sides). Cover the bowl.
• Bulk rise: Let the dough rest, covered, in the bowl until it has increased by about 75% (this usually takes about 3–4 hours at room temperature). If your kitchen is cool, place the covered bowl in your oven with only the oven light on to keep it slightly warm.
• Lightly flour your work surface. Gently turn the dough out onto the surface, handling it gently to preserve air. Flatten it into a rough rectangle, fold each long side toward the center, then roll the dough up and shape it into a tight round by pulling and tucking the dough in a circular motion 3–4 times. Finish with the seam on the bottom and the top smoothed.
• Place the shaped dough seam-side up into a well-floured banneton or a bowl lined with a heavily floured kitchen towel. Cover the dough with plastic wrap or a towel and place it in the refrigerator to cold-proof for at least 2 hours (you may cold-proof up to 48 hours if desired).
• At least 45 minutes before baking (or while the Dutch oven heats if you prefer), preheat your oven to 425°F with the Dutch oven (with its lid on) inside. If you use a baking stone or a baking sheet to protect the bottom of the loaf, place it on the lower rack before preheating.
• When the oven and Dutch oven are fully hot, remove the dough from the refrigerator. Invert the banneton bowl to release the dough onto a piece of parchment paper so the seam is now on the bottom (seam-side down). Lightly flour the top, then score the top of the loaf (a simple X or a single long slash).
• Using the parchment, lift the dough and carefully place it into the preheated Dutch oven. Cover and bake for 40 minutes.
• After 40 minutes, remove the lid and bake uncovered for an additional 10–15 minutes, until the crust reaches your desired color and crispness.
• Remove the loaf from the Dutch oven and transfer it to a wire rack. Cool for at least 1 hour before slicing to allow the crumb to finish setting.
• Slice with a bread knife or electric knife and serve.