1. Mix together the biga ingredients in a large bowl, stir thoroughly until incorporated.  Cover with plastic wrap and let sit at room temperature (70F) for at least 8 hours, or up to 24 hours.  (You can leave it in the fridge for up to 3 days if desired; let sit at room temperature for 30 minutes before proceeding to the next step).

2. Add flour, yeast, and water; mix until thoroughly incorporated.  It will be a very sticky dough.  Cover bowl with plastic wrap and let sit at room temperature for 15 minutes.  Add salt and mix in thoroughly.  Cover bowl with plastic wrap; let rise at room temperature for 30 minutes.

3. Gently fold the dough 8 times with a greased spatula, turning bowl 90 degress each time.  Cover bowl with plastic wrap and let rise at room temperature for 30 minutes.  Repeat this step twice for a total of 3 foldings and 3 rises.

4. Preheat oven to 500F; place baking stone or overturned baking sheet on top rack.

5. Flour a work surface and your hands well, then gently ease dough out of bowl.  Cut it in half, then gently form each half into a 5" round.

6. Oil two 9" cake pans (2T oil each), then sprinkle salt in each pan (1/2T each).  Place dough upside down in the pan, swirl it around to coat with oil, then gently flip dough over.  Cover pans with plastic wrap, and let sit 10 minutes.

7. Gently stretch dough to the edges of the pans (if it doesn't stretch easily, set it aside another 5 minutes or so and try it again).  Poke each loaf with a fork 20-25 times, being sure to burst any really large holes.  Sprinkle rosemary over the top of each loaf (1T each).   Let rest about 10 minutes.

8. Place in oven, turn oven down to 450F.  Bake 25-28 minutes, switching placement halfway through.

9. Remove from oven, let cool on wire rack for 5 minutes, then remove bread from pans.  Brush the tops with any oil that's left in the pans.  Let cool for another 30 minutes.  Serve and enjoy!