In a large mixing bowl, whisk together, flour, salt and yeast.
Add the warm water and mix together with a large spoon until combined.
Cover the bowl with plastic wrap and then cover with a tea towel.
Put the bowl in a warm place and let the dough rise for 3 hours.
After two hours have passed, put your skillet in the oven. On the bottom rack, add a pyrex baking dish or bowl filled with 2 inches of water. Preheat your oven to 475° F for 45 minutes.
Once the dough has risen for 3 hours, has doubled in size and the top is bubbly, turn it out onto a floured board or counter. With floured hands, quickly form the dough into a ball. DO NOT KNEAD.
Carefully remove hot cast iron skillet from the oven and line with parchment paper. (If you do not have parchment, you can add a couple of teaspoons of cornmeal to the skillet to keep the dough from sticking.)
Add the bread dough to the skillet.
With a sharp knife, make a large "X" onto the top of the dough and return to the oven.
Bake for 30-45 minutes until the bread is golden brown.
Transfer bread to a wire cooling grid for 30 minutes before slicing.
Enjoy!