Overnight Rosemary Focaccia

Method

1. The night before, whisk the flour, kosher salt and yeast in a large bowl, add the water and mix with a wet hand until no dry flour remains, about 2 minutes. Cover and rest 30 minutes.
2. With a wet hand, lift one edge of the dough, fold it over the center, turn the bowl a quarter turn and repeat four times. Rest 30 minutes, fold again, rest 30 more and fold a last time, then cover tightly and refrigerate 12 to 24 hours.
3. Pour 2 tablespoons of the oil into a rimmed half-sheet pan (13 by 18 inches) and scrape the cold dough into it, turning once to coat. Stretch it gently toward the corners, resting 15 minutes if it springs back, then cover and let it rise at room temperature about 2 hours, until puffy and jiggly with bubbles under the surface. Heat the oven to 450°F with a rack in the lower third during the last 30 minutes of the rise.
4. Oil your fingertips and dimple the dough firmly down to the pan, then drizzle in 2 tablespoons of oil and scatter on the rosemary and flaky salt.
5. Bake 22 to 25 minutes, until deep golden on top and crisp underneath when you lift a corner with a spatula. Brush the last tablespoon of oil over the hot surface, slide the focaccia onto a rack and cool 10 minutes before cutting.