Combine the yeast and the warm water in a small bowl and stir with a fork to dissolve the yeast. Let stand for 3 minutes. Combine the flours and salt in a large bowl. Pour the cool water and the yeast mixture over the flour, and mix with your fingers to form a shaggy mass. Move the dough to a lightly floured work surface and knead for 4 minutes. It should be supple and resilient, but not too smooth at this point. Let the dough rest on the work surface for 20 minutes, covered with plastic wrap or a light towel. (This rest period is the autolyse.)
Knead the dough for 6 to 8 minutes. Don't overknead it: The dough should be smooth, stretchy, and resilient. Place the dough in a lightly oiled bowl, turn it in the bowl to coat with oil, and cover it with plastic wrap. Let rise at room temperature ( 75 to 77 degrees F) for 1 1/2 to 2 hours, or until nearly doubled in volume.
Gently deflate the dough and fold it over itself in the bowl. Reshape it into a ball and cover with plastic wrap. Let it rise for 1 1/4 hours or until it has nearly doubled again. Gently deflate the dough again, reshape into a round, cover, and let rise for about 1 hour. Place the dough on a very lightly floured surface and divide it into 3 equal pieces (about 10 ounces each). Gently stretch one piece into a rectangle, leaving some large bubbles in the dough. Fold the top third down and the bottom third up as if you were folding a business letter. Now form the loaf into a log by rolling the dough over from left to right and sealing the seam with the heel of your palm. Fold the dough over about 1/ 3 of the way each time, seal the length of the loaf, then repeat. You want to gently draw the skin tight over the surface of the baguette while leaving some air bubbles in the dough. Seal the seam, being careful not to tear the skin of the dough or deflate its airy structure. Set aside on the work surface to relax before elongating it, and repeat the shaping process with remaining pieces of dough.
Now elongate each baguette, starting with the first one you shaped, by rolling it back and forth on the work surface. Begin with both hands over the center of the loaf and work them out to the ends until the loaf reaches the desired length. (Don't get carried away, or the baguettes won't fit in your oven!) Place the finished loaves on a peel or upside down baking sheet lined with parchment paper and generously sprinkled with cornmeal or on a baguette pan. Cover the loaves with well oiled plastic or a floured cloth and let rise for 30 to 40 minutes until the loaves are slightly plump but still not doubled in volume. The final rise is short, because you want the baguettes to be slightly under proofed; this will give them a better oven spring, resulting in loaves with a light, airy crumb and more flared cuts.
Thirty minutes before baking, preheat the oven to 500 degrees F. Place a baking stone in the oven to preheat, and place an empty water pan directly under the stone. Use a very sharp razor blade or lame to make 3 to 5 slashes, depending on the length of your loaves, on the top of each baguette. The cuts should run from one end of the loaf to the other, rather than across it, and the blade should be held at a 30 degree angle to the loaf so that the cuts pop open in the oven. Be careful not to press down too hard, or you may deflate the loaves. Using a plant sprayer, mist the loaves.
Gently slide the loaves onto the preheated stone, or place the baguette mold in the oven. Pour 1 cup of very hot water into the water pan and quickly close the oven door. After 1 minute, mist the loaves and oven walls 6 to 8 times and close the door. After 2 more minutes, spray the loaves and the oven walls again.
Bake for 12 minutes, then lower the oven temperature to 400 degrees F and bake for 25 to 30 minutes longer until the loaves are golden brown and crisp. Move them to a rack to cool.
Enjoy your baguettes still slightly warm with some soft, ripe French cheese and a glass of wine.
Note: If cake flour is not available, you can use the same amount of unbleached allpurpose flour, but cake flour will give the baguette a lighter texture.