In a large bowl, whisk together the flour, salt, and instant yeast. Add the water. Using a rubber spatula, mix until the liquid is absorbed and the ingredients form a sticky dough ball.
Cover the bowl, and let rest for 30 minutes, then stretch and fold the dough.
Rub the surface of the dough lightly with olive oil. Cover the bowl with a lid or plastic wrap and place in the refrigerator immediately for at least 12 hours or for as long as three 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 the center of each pan. Using two forks, deflate the dough and split it into two equal pieces. Place one piece into one of the prepared pans.
Let the dough balls rest for 3 to 4 hours.
Preheat the oven to 425°F. If using rosemary, sprinkle it over the dough. Pour a tablespoon of oil over each round of dough.
Press straight down to create deep dimples. Sprinkle with flaky sea salt.
Transfer the pans to the oven and bake for 25 to 30 minutes, until golden and crisp.
Let it cool for 10 minutes before cutting and serving.
