4cupsall-purpose flour or bread floursee notes above
2teaspoonskosher salt
2teaspoonsinstant yeastsee notes above if using active dry
2cupslukewarm watermade by combining 1/2 cup boiling water with 1 1/2 cups cold water
butter for greasing
4tablespoonsolive oil, divided
flaky sea salt, such as Maldon
1 to 2teaspoonswhole rosemary leaves, optional
Instructions
In a large bowl, whisk together the flour, salt, and instant yeast. Add the water and mix until a sticky dough forms. Rub the dough lightly with olive oil, cover, and refrigerate for at least 12 hours or up to 3 days.
Line two 8- or 9-inch pie plates or a 9×13-inch pan with parchment paper or grease with butter. Pour a tablespoon of oil into each pan (or 2 tablespoons for a 9×13-inch pan).
Deflate the dough, split into two equal pieces (or keep whole for a 9×13-inch pan), and place in the prepared pans. Roll the dough in the oil to coat, forming a rough ball. Let rest for 3 to 4 hours.
Preheat the oven to 425°F. Sprinkle rosemary if using, pour a tablespoon of oil over each round, and press deep dimples into the dough with your fingers. Sprinkle with flaky sea salt.
Bake for 25 to 30 minutes, until the underside is golden and crisp. Transfer to a cooling rack and let cool for 10 minutes before serving.
Store cooled focaccia in an airtight bag at room temperature for up to 3 days or freeze for up to 3 months. Reheat at 350°F for 15 minutes to revive the crust.
Notes
For best results, ensure the dough is well-oiled before refrigeration to prevent drying. The long fermentation time enhances flavor and texture.