Step 1: In a large bowl, combine the warm water, yeast, and sugar. Stir gently and let sit for 5-10 minutes until foamy. This indicates your yeast is active.
Step 2: Add the flour and 2 teaspoons of fine sea salt to the yeast mixture. Using a wooden spoon or your hands, mix until a shaggy, sticky dough forms and no dry streaks of flour remain. Do not overmix or knead extensively. Drizzle 2 tablespoons of olive oil over the dough, ensuring it's lightly coated. Cover the bowl tightly with plastic wrap and refrigerate for at least 12 hours, or up to 24 hours. (This slow cold ferment is key for flavor and texture.)
Step 3: The next day, remove the dough from the refrigerator. Lightly oil a 9x13 inch baking pan with 2 tablespoons of olive oil. Gently transfer the dough to the prepared pan. With oiled hands, gently stretch and fold the dough over itself a few times in the pan to form a rough rectangle. Cover loosely with plastic wrap or a damp kitchen towel and let it rest in a warm place for 1-2 hours, or until it has noticeably puffed up and is jiggly.
Step 4: Once the dough has risen, generously drizzle the remaining 1/4 cup of olive oil over the top. Using your fingertips, gently press down to create deep dimples all over the surface of the dough. Be careful not to deflate the dough entirely. Press the fresh rosemary sprigs into the dimples and sprinkle generously with flaky sea salt. Let rest for another 15-20 minutes while you preheat your oven.
Step 5: Preheat your oven to 425°F (220°C). Bake the focaccia for 20-25 minutes, or until the top is golden brown and the bottom sounds hollow when tapped. If the top is browning too quickly, you can loosely tent it with foil.
Step 6: Remove the focaccia from the oven and immediately transfer it to a wire rack to cool slightly. For an extra rich flavor, you can brush with a little more olive oil while warm. Slice and serve warm or at room temperature. Enjoy your delicious Focaccia Bread Recipe!