01 - Combine bread flour and water in a large bowl, mixing until just combined. Cover and let rest for 30–45 minutes to develop gluten structure.
02 - Add sourdough starter and sea salt to the dough. Mix thoroughly until completely incorporated and smooth.
03 - Complete four sets of stretch-and-fold every 30 minutes over 2 hours, keeping dough covered between sets to develop strength.
04 - Let dough rest at room temperature for 1 hour after the final fold to continue fermentation.
05 - Turn dough onto lightly floured surface and gently stretch into a rectangle. Spread pesto evenly, leaving a 1-inch border, and sprinkle with 1.4 oz (about 3 tablespoons) Parmesan.
06 - Roll dough into a log from the short end, then shape into a round boule or batard. Place in floured banneton or bowl, seam side up.
07 - Cover and let rise at room temperature for 2–3 hours, or refrigerate overnight (8–12 hours) for enhanced flavor development.
08 - Preheat oven to 450°F with Dutch oven or baking stone inside for at least 30 minutes to ensure proper heat retention.
09 - Turn dough onto parchment paper. Brush top with olive oil and sprinkle with remaining Parmesan. Score loaf as desired.
10 - Transfer to preheated Dutch oven and bake covered for 20 minutes to create steam and oven spring.
11 - Remove lid and continue baking for 18–20 minutes until golden brown and crusty, with internal temperature reaching 200°F.
12 - Cool on wire rack for at least 1 hour before slicing to ensure proper texture and prevent gummy crumb.