Makes 1 large round, or two small loaves, or one big loaf.
1 cup warm water (about 110 degrees – if you are not sure about the chlorine content in your
tap water, use bottled and heat it carefully on the stove)
1 cup starter
2 cups all-purpose flour (we like King Arthur)
All of the above sponge
1½ to 1¾ cups all-purpose flour
2 teaspoons salt
Make the sponge:
In a large mixing bowl, place water and whisk in the starter. Stir in the flour and wrap bowl well with saran wrap and let rest room temperature for at least 8 hours and up to 14.
Make the dough:
Stir the rested sponge to deflate it and stir in 1 ¼ cups flour and the salt.
Knead dough by hand for about 5 minutes until elastic but still very soft. Scrape dough into a lightly oiled bowl, wrap and let dough rise at room temperature until doubled, about an hour.
Scrape dough onto a floured work surface and press to deflate. Form and even sphere tucking sides under loaf. Invert into a bread basket lined with a floured towel, if you like, or just let rest on a floured board, loosely cover with plastic wrap and let rest 1 hour.
Preheat oven to 500 degrees. Turn loaf onto a pizza peel covered with cornmeal. Use a razor blade to slash diagonal lines across top of loaf, and slide onto a baking sheet or pizza stone. Then lower temperature to 450 degrees. After loaf has baked 25 minutes, lower temperature of oven to 350 degrees, and let cook 20-30 minutes until internal temperature is 210 degrees.
Remove from oven and let cool on a rack.