Sourdough Focaccia Bread in 5 Hours with Crispy Golden Crust

Instructions:

1. In a large mixing bowl, whisk the active sourdough starter into the warm water until it is completely milky and dissolved.
2. Add the bread flour and fine sea salt to the water mixture. Mix by hand until a shaggy, sticky mass forms with no dry flour remaining.
3. Cover the bowl and let the dough rest for 30 minutes for the autolyse stage, allowing the flour to fully hydrate.
4. Perform 3 sets of 'stretch and folds' over the next 90 minutes to build gluten structure, then allow the dough to bulk ferment at room temperature until doubled in size and bubbly (approx 4-6 hours).
5. Pour 30g of olive oil into a 9x13 inch metal baking pan. Transfer the dough to the pan, turning it once to coat in oil. Let it proof for another 1-2 hours until the dough fills the corners.
6. Preheat your oven to 425°F (218°C). Drizzle the remaining 30g of olive oil over the top. Use your fingers to dimple the dough deeply, creating pockets.
7. Sprinkle with flaky sea salt and fresh rosemary leaves. Bake for 25 minutes or until the top is mahogany-colored and the bottom is crisp.