# What You’ll Need:
→ Sourdough Starter
01 - 3.5 oz active sourdough starter (100% hydration)
→ Dough
02 - 14 oz bread flour
03 - 10 fl oz lukewarm water
04 - 0.35 oz fine sea salt
05 - 0.68 fl oz extra-virgin olive oil
→ Topping
06 - 2 medium yellow onions, thinly sliced
07 - 1 tablespoon olive oil
08 - 1 teaspoon flaky sea salt
09 - 1 teaspoon fresh rosemary leaves
10 - Freshly ground black pepper to taste
# How-To:
01 - In a large mixing bowl, combine sourdough starter, bread flour, and lukewarm water until a shaggy dough forms. Cover and allow to rest for 30 minutes to develop gluten structure.
02 - Add fine sea salt and extra-virgin olive oil to the rested dough. Mix thoroughly until both ingredients are fully incorporated throughout.
03 - Over the next 2 hours, perform 3 to 4 sets of stretch and fold techniques at 30-minute intervals. This builds optimal gluten development and creates the characteristic airy crumb structure.
04 - Cover the bowl and let the dough rise at room temperature for 6 to 8 hours until it doubles in volume.
05 - Generously oil a 9x13-inch baking pan. Gently transfer the dough to the pan without deflating. Using oiled fingers, stretch and press the dough to fill the pan evenly.
06 - Cover the pan and refrigerate for 8 to 12 hours. This extended cold fermentation develops superior flavor complexity and improves texture.
07 - While dough ferments, heat 1 tablespoon olive oil in a skillet over medium-low heat. Add sliced onions and cook, stirring occasionally, for 20 to 25 minutes until deeply golden, tender, and sweet. Allow to cool completely before using.
08 - Remove dough from refrigerator and allow it to come to room temperature, approximately 1 hour, before baking.
09 - Preheat oven to 425°F. Dimple the entire dough surface with your fingertips. Drizzle with additional olive oil, then evenly distribute caramelized onions, flaky sea salt, fresh rosemary, and freshly ground black pepper across the top.
10 - Bake for 25 to 30 minutes until the surface is golden brown with crispy, caramelized edges.
11 - Remove from oven and allow to cool slightly before slicing. Serve warm for optimal flavor and texture.
