Place a metal pan on the lowest rack in your oven. DO NOT USE A GLASS PAN, it will crack when you add water. Place a baking stone or baking steel on the rack above it.
Preheat oven to 450℉.
Prepare a pizza peel by spreading a thin layer of cornmeal onto the surface. Be generous with the cornmeal. Set aside.
Remove dough from the fridge and dust some flour onto your hands. Pull up a handful of dough (about the size of a grapefruit) and cut off with kitchen shears or a serrated knife, or just pinch it off with your hands.
Hold the ball of dough in your hands and add more flour to them as needed so the dough doesn’t stick to your hands. Gently stretch and turn the ball in your hands as you shape the loaf pulling the dough tight to form a smooth surface on the top of the ball. Don’t overwork the dough, this process should take less than a minute.
Place the formed loaf onto the prepared pizza peel and allow the dough to rest for 40 minutes while the oven is preheating. The dough will relax, spread, and flatten.
Just before putting the loaf in the oven, dust the top liberally with flour and slash the dough with a sharp knife or a bread lame. Make 3-5 cuts about a 1/2 inch deep along the top of the loaf. Slide the loaf off the pizza peel and onto the preheated baking stone or steel in the oven.
Quickly but carefully pour 1 cup of water into the metal pan on the lower rack and close the oven door.
Bake loaf for 30-35 minutes, or until the crust is richly browned and firm to the touch.
You may need to make some adjustments to the bake time depending on the size of your loaf. When removing the loaf it should audibly crackle or sing when initially exposed to room temperature and it should sound hollow when you tap it with your fingers.
Cool for at least 2 hours on a wire rack before cutting into the loaf. Cutting into it while it's still hot will result in an unpleasant, gummy texture.
Once fully cooled, slice and slather with soft butter to serve.