Steps

Step 1

In a large bowl, whisk together the flour, kosher salt and yeast. Add the warm water to the flour mixture and stir until all the flour is incorporated and a sticky dough forms. (Expect a very wet dough; no kneading required.) Pour 2 tablespoons oil into a medium bowl. Transfer the dough to the bowl, turn to coat, and cover tightly with a lid or plastic wrap. Place in the refrigerator to rest for at least 24 hours or for up to 2 days.

Step 2

When you’re ready to bake, brush the inside of a 9-by-13-inch baking sheet with oil. Remove the dough from the refrigerator and transfer to the prepared pan. Using your hands, spread the dough out as much as possible, adding oil to the dough if needed to keep it from sticking. (Don’t worry if the dough doesn’t yet cover the full pan; it will once it relaxes and rises.) Place the dough in a warm place and let rise until about doubled in bulk. The rising time will vary considerably depending on the season. (In the summer, it may take only 20 minutes for the dough to warm up and rise; in the winter, it can take 1 hour or more.) When the dough is ready, it should be room temperature, spread out on the sheet and fluffy.

Step 3

Heat the oven to 450 degrees. Using your palms, pat down the focaccia to an even thickness of about 1 inch, then, using your fingertips, dimple the entire dough. Drizzle it with the remaining 2 tablespoons olive oil. Sprinkle the entire surface of the focaccia evenly with the sea salt and Rosemary.

Step 4

Bake, rotating once front to back, until the top is uniformly golden brown, 20 to 25 minutes. Transfer the focaccia on the baking sheet to a wire rack to cool, then slide out of the pan. Enjoy it hot.