In a large bowl, mix bread flour and water until combined. Cover and rest for 30-60 minutes. Add active sourdough starter and salt, mixing with your hands until fully incorporated.

Cover and let the dough rest in a warm place for 4-6 hours. Perform 3-4 sets of stretch and folds every 30 minutes during the first 2 hours. The dough is ready when it has risen by about 30-50%.

Gently stretch the dough into a large rectangle on a lightly floured surface. Spread the pesto evenly, leaving a small border. Sprinkle with half of the Parmesan cheese. Fold the dough like a letter, then roll it into a tight log.

Shape the dough into a boule or batard and place it seam-side up in a floured banneton. Cover and refrigerate for 12-24 hours.

Preheat oven and Dutch oven to 500°F (260°C). Place dough on parchment paper, score the top, and sprinkle with the remaining Parmesan. Bake in the Dutch oven, covered, for 20 minutes. Remove the lid, reduce heat to 450°F (230°C), and bake for another 20-25 minutes until deeply golden.

Remove the bread from the Dutch oven and let it cool completely on a wire rack for at least 2 hours before slicing.