01 -
Combine sourdough starter, sugar, water, and flour in a large bowl until a rough dough forms. Cover and let rest in a warm place for 1 hour.
02 -
Add salt and olive oil to the dough. Knead by folding and pinching until fully incorporated.
03 -
Transfer dough to a covered container; let rise in a warm spot for 1.5 hours. Perform a stretch and fold every 30 minutes, shaping the dough into a square.
04 -
Place dough in a well-oiled baking sheet or parchment-lined pans; rest in a warm place for 3 to 4 hours until bubbly and spread. Alternatively, refrigerate overnight up to 3 days, then bake directly from cold.
05 -
Preheat oven to 450°F (232°C) with a baking stone or steel positioned in the center if available.
06 -
Dimple dough surface thoroughly by pressing fingers down to the pan base. Drizzle with olive oil, sprinkle salt and rosemary evenly.
07 -
Bake on the stone or steel for 20 minutes until golden and bottom is crisp. If no stone, bake on lower oven rack to ensure crispness.
08 -
Remove from oven and drizzle with additional olive oil before slicing and serving.