Scrape work surface and, working with one piece of dough at a time, turn the dough seam side down, cup right hand over center of dough, and place cupped left hand over right. Push dough forward with heels of hands and pull it back with fingertips. When it is about 14 inches long, press down on ends to taper them. Lift shaped dough, seam side up, onto floured towel and pull a pleat of towel up to cradle it. When pieces are shaped, fold end of towel over loaves and let rest 2 hours, or until dough has risen and barely springs back when poked.
Position rack in lower third of oven and line with a baking tile.
Place a cast-iron skillet on oven bottom. Preheat oven to 425 F. Flour a baker's peel. Flip one batard onto the peel and slash 3 diagonal cuts in the top. Transfer immediately to the oven. Slash and transfer the other two batards as fast as possible.