Preheat the oven to 450 degrees and place a sheet pan, or oven-safe skillet on the bottom rack to allow it to heat up.
When you are ready to bake your bread, remove the plastic wrap from the dough.To prevent sticking, cut out a piece of parchment paper that is the size of the bottom of the round and stick it to the dough before inverting into the skillet. Use a pizza peal or a cutting board to invert the dough. Then slide the dough into the cast iron skillet from there.
If you only have one cast iron skillet that is 10 to 12 inches wide, then bake each dough separately.
If you wish to bake two rounds and you only have one cast iron skillet, then just bake one round at a time and keep one piece of dough covered in the fridge.
For a large round loaf, score the dough with one line down the middle and diagonal lines down the sides. You can also score with a Plus sign too with small diagonal lines in between.
Place the loaves or the rounds in the middle rack of the oven. Throw in one cup of ice onto the sheet pan or skillet on the bottom rack and close the oven door imediately to trap the steam.
Bake for about 35-45 minutes, or until the top is a deep brown. For the round, you can check for doneness by removing it from the pan and tapping the bottom. If it sounds hollow, it's ready.
Let cool for at least 30 minutes to one hour before cutting into the bread.
You can cool the bread completely, wrap in plastic wrap and freeze for future use.