In a stand mixer bowl with dough hook, add starter.
Pour water on top and sprinkle on the yeast. Let sit for 5 minutes.
Add salt and flour, gradually.
In the stand mixer, blend on low for 5 minutes until dough pulls away from the sides and forms into a nice ball.
Oil a glass bowl, one large enough to handle a double rising of the dough.
Place dough in bowl, cover with plastic wrap to let double for approximately 1 1/2 hours.
Sprinkle flour on work surface and add risen dough.
Sprinkle a 16" x 12" pan with cornmeal.
Cut dough in half.
Place dough side-by-side on pan, but not touching.
Cover and let rise for 1 hour.
Preheat oven 425° F (218° C).
After 1 hour, lightly sprinkle dough with flour.
Cut a tic-tac-toe pattern on top of dough with a very sharp serrated knife.
Place pan in middle of oven.
Quickly spray water inside the top of the oven. It's okay if some water gets on the dough.
Bake for 25 to 30 minutes. While baking, spray water again after baking 10 minutes and again at 20 minutes.
Check for doneness: the bread should be brown on top and dark brown on the bottom. Thump the top of the bread to hear an echo, hollow sound. Cool on wire racks
From Heidi Kleyn: "Use the starter on Day 10 before adding the flour, milk and sugar. Experiment with different flours for this bread. Try using 4 cups of flour and 1 cup of whole wheat flour."From Cathy Wagner List: "This bread is the best I've ever had! I used a stand mixer and followed the directions exactly. I've made it twice and the bread came out better the second time when I only mixed with dough hook for 2:30 minutes. It's important to pay attention to dough clinging perfectly and clean sides of the bowl. The first time I used the whole 5 minutes with mixer and bread was a little tough. Second time I just judged by the mixer and dough with clean sides of bowl and it was only 2:30. I put pan in bottom of oven while preheating and when I put bread in, I threw in a cup of cold water in the pan to steam. It worked great. This bread is epic."