3. Switch to the mixer’s dough hook, scoop in the remaining 2 cups of bread our and the yeast mixture, and knead on low, adding more our, a bit at a time if needed, until the mixture comes together into a rm, elastic dough that cleans the sides of the bowl, about 7 minutes. 4. Line a 13-by-18-inch rimmed baking sheet with parchment and sprinkle with coarse cornmeal; set aside. Turn the dough out onto a lightly floured surface and knead a few times. If the dough is sticking, sprinkle with a bit of our. Cut it in half and shape each piece into a ball. Cup one ball in both hands and stretch the sides of the dough down and under, making an oval, then turn 90 degrees and repeat, creating a smooth round with a tight surface. Securely pinch the seams closed underneath and turn seam side down. Repeat with the second ball of dough. Dust the loaves heavily with bread our. Transfer to the baking sheet, cover with a tea towel, and let rise in a warm, draft-free spot until doubled in size, about 45 minutes. 5. Position a rack in the middle of the oven. Place a heavybottomed skillet on the oor of the oven, and crank up the heat to 475°F. 6. Uncover the loaves and slide the baking sheet into the oven, then lean back and pour 1½ cups of water into the skillet. Close the door quickly. (The steam will create a lovely crispy crust.) Wait for 5 minutes, and repeat. Bake until the loaves are golden brown and crackly—charred in spots isn’t a bad thing—and sound hollow when thwacked on the bottom, 35 to 45 minutes. Transfer to a rack to cool until just warm. These are best devoured the same day.