sourdough focaccia

Whisk the active sourdough starter with lukewarm water and sugar in a large mixing bowl until fully dissolved into a milky slurry. Incorporate the white flour until a shaggy dough forms, ensuring no dry streaks remain. Perform a gentle set of stretch and folds to initiate gluten development, then cover and rest for 30 minutes. Dimple the fine sea salt and the remaining water into the dough. Perform a second set of stretch and folds until the salt and hydration are fully absorbed. Complete 3 additional series of stretch and folds, allowing the dough to rest for 30 minutes between each session to build strength and elasticity. Allow the dough to bulk ferment at room temperature until visibly aerated, jiggly, and increased in volume by roughly 30% to 50%. Generously pool extra-virgin olive oil into the base of a high-sided baking tray. Gently transfer the dough, turning it once to coat the exterior in oil, then cover and cold retard overnight in the fridge. Remove the tray from the fridge and allow the dough to proof at room temperature for 2.5 hours (or up to 4 hours) until it relaxes to the edges of the pan and becomes exceptionally bubbly and highly extensible. Drizzle the surface with additional oil and deeply dimple the dough with oiled fingertips to degas the largest bubbles. Bake in a preheated oven using conventional heat (top and bottom, no fan) at 220°C for 35 minutes, until the crust exhibits a deep, golden-brown oven spring and a crisp bottom.