For The Poolish:
1 ½ cups (200 g) bread flour
1 scant cup (200 ml) water, room temperature
¼ teaspoon instant yeast
For The Dough:
2 ⅔ cups (350 g) bread flour
1 cup (240 ml) water, room temperature
2 teaspoons salt
½ teaspoon instant yeast
Instructions
Make The Poolish:
Combine the flour, water, and yeast in a medium bowl. Stir with a wooden spoon until fully combined and the mixture is smooth. Cover with plastic wrap and allow it to ferment at room temperature for 15 to 20 hours.
Make The Dough:
Add the poolish and all ingredients for the dough to the bowl of a stand mixer fitted with the paddle attachment. Mix on low speed until all the flour is moistened, about 2 minutes. Increase the speed to medium-low and mix until dough forms into a mass and pulls away from the sides of the bowl, about 6 minutes.
Switch to the dough hook attachment and mix on medium-low until dough becomes smooth and shiny, about 10 minutes. The dough will be soft, wet, and sticky much like batter.
Lightly coat the inside of a large bowl with olive oil or nonstick spray. Use a silicone dough scraper to scrape the dough into the bowl. Cover with plastic wrap and let rise for 1 hour at room temperature.
Using a greased scraper or damp fingertips, gently grab one side of the dough, lift and stretch it over the top of itself. Turn the bowl 180 degrees and stretch the same way. Rotate 90 degrees, stretch and fold. Rotate 180 degrees to stretch and fold the final side. Flip the dough over so the bottom becomes the top. Cover with plastic wrap and let rest at room temperature for 45 minutes.
Repeat folding two more times, then cover with plastic wrap and let sit for an additional 45 minutes after each.
Adjust the oven racks so that one is in the lower-third position (just below the center) and one is at the very bottom position.
Place a cast-iron skillet on the lowest rack and an inverted baking sheet on the upper rack. Heat the oven to 450°F. It's important to let the oven preheat for at least an hour to ensure it is hot enough.
Liberally dust your work surface with flour and let the dough slide out of the bowl onto the counter. Be very gentle here so you don't knock all the air out of the dough and try to handle the dough as little as possible. Liberally dust the top of the dough with flour. Using 2 well-floured bench scrapers, carefully manipulate the dough from the sides to form a square. Take care not to put pressure on top of the dough.
Cut the dough in half, down the middle of the square. Gently shape each half into loaves by using the bench scrapers to manipulate the sides.
Invert a large baking sheet and place a sheet of parchment paper across the top. Dust liberally with flour. Using both bench scrapers, slide them under both ends of the dough and transfer the dough to the prepared parchment paper. Repeat with the remaining loaf. Use your fingertips to gently poke the surface of each loaf as you shape it into a rectangle.
Cover with a lint-free cloth to prevent the loaves from drying out. Proof in a draft-free place until puffy and the surface develops small bubbles, about 30 minutes.
Have 1 cup of ice ready. Mist the loaves with water and carefully slide the parchment with loaves on the heated baking sheet in the oven using a jerking motion. Immediately drop the ice into the cast-iron pan on the bottom rack. Quickly close the oven door.
Bake, until the crust is a deep golden brown, about 25-35 minutes. The internal temperature of the bread should be 210-215°F.
Transfer to a rack to cool completely before slicing and serving
