Lightly sprinkle flour and/or cornmeal onto a large nonstick baking sheet. Take the cold dough out onto a floured surface. Cut the dough in half using a sharp knife or bench scraper; expect some air bubbles to deflate.
Put the dough halves on the prepared baking sheet, shaping them into roughly 9×3 inch long loaves, spaced about 3 inches apart.
Cover loosely and let them rest for 45 minutes. These loaves will be baked on the same prepared baking sheet. During this 45 minutes, preheat the oven to 475°F (246°C).
When it's time to bake, use a very sharp knife, bread lame, or even kitchen shears to make three shallow slashes about half an inch deep on top of each bread loaf. If the loaves have flattened out during the resting period, gently shape them back into narrow loaves using floured hands along the sides.
For a crispier crust, do this optional step: After preheating the oven and scoring the bread, place a shallow metal or cast iron pan on the bottom rack. Pour in 3-4 cups of boiling water and quickly shut the oven door to trap the steam inside. This steam helps make the crust crispier.
Put the shaped and scored dough on the floured/cornmeal-dusted pan into the preheated oven on the middle rack. Bake for 30-45 minutes until the crust is golden brown.
To check if it's done, tap the loaves - if they sound hollow, they're ready. Or, use an instant-read thermometer; it's done at 195°F (90°C).
Take the bread out of the oven and let it cool for at least 5 minutes before slicing and serving.
For leftovers, keep them loosely covered at room temperature for up to 5 days, or in the refrigerator for up to 10 days.