The night before, feed your starter and allow it to sit on the counter overnight.
In the morning, your starter should be active and bubbly. If not, feed it again and allow it to sit another hour or two until ready.
In a glass mixing bowl combine the starter, warm water, flour, and salt. Mix well with your hands or a spoon.
On a floured surface, knead the dough for several minutes until it's fairly smooth and not sticky.
Place the dough in the bowl, cover it with a tea towel, and set it in a warm place for the day, about 8 to 9 hours. It should double in size.
When ready to bake, place the baking stone in the center of the oven and the metal dish on a rack below it. Preheat the oven to 450 degrees F.
Divide the dough into two equal pieces. Roll each piece out into an oblong, about 12 inches long. Tuck in the ends for a nice shape. Lay each loaf on the parchment or baking mat-lined cookie sheet or pizza peel. Allow to sit in a warm place while the oven preheats, about 20 minutes.
While waiting, mix up the egg wash. Whisk an egg with a sprinkle of water in a small bowl. Use a pastry brush to spread the egg wash all over the tops and sides of the loaves right before baking.
When ready to bake, use a sharp knife or a bread lame to make 3 or 4 diagonal cuts across the tops of the loaves.
Open the oven and carefully slide the parchment paper or baking mat with the loaves onto the baking stone. Pour a cup of ice cubes into the metal dish and close the oven door.
Bake for about 15 to 18 minutes, or until the loaves are golden brown and cooked through. Allow cooling on a wire rack before slicing.