Mix the yeast and the warm water in a large bowl or in the bowl of a stand mixer.
Add the whole-wheat flour and ¾th cup of all-purpose flour to the bowl and mix with the dough hook or with a wooden spoon until everything's thoroughly mixed together.
Cover the bowl with plastic wrap and let it stand overnight or for eight hours.
Now add the salt and the remaining all-purpose flour to the bowl, a cup at a time, kneading and mixing. Drizzle in the olive oil. You want a smooth but not stiff dough. Continue to knead for another eight minutes.
Shape the dough into a smooth ball and then place in a greased bowl, turning over once to coat the top with the oil. Cover with plastic wrap or a kitchen towel and set it aside to rise in a warm place for an hour or until it has doubled in size.
Punch down the dough and divide into two. Shape each half into a loaf by punching it into a round about eight inches in diameter and then rolling it up into a loaf. Pinch the seams together and tuck them underneath.
Sprinkle some cornmeal on a lightly greased baking sheet. Place the loaves as far apart as you can on the sheet, giving enough room on all sides for the loaves to rise.
Cover with a kitchen towel and set aside for two hours. The loaves should double in size. In the last half hour of rising, preheat the oven to 425 degrees Fahrenheit. Place a baking pan with water in the bottom rack of the oven.
Just before you place the loaves in the oven, make two or three sharp slashes on the top of each loaf using a very sharp knife. You want to use a swift motion so as to not deflate the bread.
Bake the bread for 40 minutes or until the bottom sounds hollow when tapped.
Remove the baking sheet to a rack and cool 10 minutes, then transfer the loaves to the rack and continue cooling them.