Mix the Base Ingredients:
Combine the flour, water, and sourdough starter in a large mixing bowl. Mix until no dry flour remains.
Utilize a clean kitchen towel to cover the bowl., then set it aside for 30 minutes. This resting period, called autolyze, is crucial for developing gluten and improving dough texture.
Incorporate Salt and Oil:
Distribute the salt evenly over the surface of the dough, followed by pouring in the olive oil to incorporate.
Gently knead the dough or use the "stretch and fold" method until the salt and oil are fully incorporated and the dough becomes smoother.
Knead for Texture:
Knead the dough for 8–10 minutes by hand or 5 minutes with a stand mixer on low speed until it reaches a smooth, elastic consistency.
Let the Dough Rise:
Place a damp towel over the bowl and let it sit at room temperature for 6–8 hours, or until it’s doubled in size.
Develop the Dough:
During the first 2 hours, perform three sets of "stretch and fold," spaced 30 minutes apart.
Grab one side of the dough, stretch it upward, and fold it over the rest. Rotate the bowl and repeat on all sides.
Prepare the Baking Pan:
Generously coat a 9x13-inch (23x33 cm) baking pan with olive oil.
Carefully transfer the dough into the pan and gently stretch it to fit the dimensions.
Final Proof:
Carefully transfer the dough into the pan and gently stretch it to fit the dimensions. Let the dough proof for 2–4 hours or until it appears puffy and well-aerated.
Pro Tip: Refrigerate the dough after shaping if you need to delay baking. It can stay in the fridge for up to 24 hours. Bring it back to room temperature before baking.
Preheat Your Oven:
Switch on the oven and set it to 450°F (230°C) at least 30 minutes ahead of baking to ensure it’s fully heated and ready.
Prepare the Surface:
Before baking, pour some olive oil over the dough and press dimples into it with your fingers.
Sprinkle coarse sea salt and your desired toppings (e.g., rosemary).
Bake to Perfection:
Place the pan in the oven and bake for 25–30 minutes or until the focaccia is golden brown with crispy edges.
Cool and Serve:
Allow the freshly baked focaccia to rest on a wire rack for at least 15 minutes, letting it cool slightly and settle before slicing for the best texture