01 - Combine bread flour and lukewarm water in a large bowl. Mix until just incorporated, cover with plastic wrap, and let rest for 30-45 minutes to allow flour hydration.
02 - Add active sourdough starter and sea salt to the rested dough. Mix thoroughly by hand or with a dough scraper until starter is evenly distributed and salt dissolves completely.
03 - Perform stretch-and-fold technique every 30 minutes for 2 hours (4 sets total). Grab one edge of dough, stretch upward, and fold toward center. Rotate bowl and repeat for all four sides. Keep covered between sets.
04 - After completing final fold set, let dough rest at room temperature for 1 hour to complete initial bulk fermentation phase.
05 - Turn dough onto lightly floured work surface. Using your hands, gently stretch into a 10x14 inch rectangle. Spread basil pesto evenly across surface, leaving 1-inch border on all edges. Sprinkle 1/4 cup Parmesan cheese over pesto layer.
06 - Starting from short end, roll dough tightly into a log shape. Tuck ends underneath and shape into a round boule or oval batard, ensuring seam is sealed on bottom.
07 - Place shaped dough seam-side up into a well-floured banneton or bowl lined with floured kitchen towel. Cover and let rise at room temperature for 2-3 hours until doubled in size, or refrigerate overnight for enhanced flavor development.
08 - Position oven rack in center. Place Dutch oven or baking stone on rack. Preheat oven to 450°F for at least 30 minutes to ensure proper heat retention.
09 - Turn proofed dough onto parchment paper. Brush surface generously with olive oil. Sprinkle remaining Parmesan cheese over top. Use lame or sharp knife to score pattern in dough surface.
10 - Carefully transfer dough with parchment into preheated Dutch oven. Cover with lid and bake for 20 minutes to create steam and initial oven spring.
11 - Remove Dutch oven lid. Continue baking for 18-20 minutes until crust achieves deep golden-brown color and bread sounds hollow when tapped on bottom.
12 - Transfer baked loaf to wire cooling rack. Let cool completely for at least 2 hours before slicing to allow internal structure to set properly.