Step 1

To make the starter: Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. Mix the starter ingredients in a small bowl, cover, and let rest at room temperature overnight., Combine the starter and the remainder of the dough ingredients. Mix, then knead the dough — by hand, mixer, or bread machine set on the dough cycle — to make a soft, fairly smooth dough.

Step 4

, Transfer the dough to a lightly greased bowl, cover the bowl or bucket, and allow the dough to rise for 90 minutes, turning it over and gently deflating it after 45 minutes. If you're using a bread machine, remove the dough when the cycle is finished, deflate it gently, and let it rest, covered, for 30 minutes., Transfer the dough to a lightly greased work surface, and divide it into three pieces., Roll each piece of dough into an 18" rope. Braid the ropes (tucking the ends under), and set the braid on a lightly greased baking sheet., Cover the braid, and let rise it rise for about 60 to 90 minutes, or until it's very puffy. Towards the end of the rising time, preheat the oven to 425°F., Uncover the braid. Brush it with the egg white glaze, and sprinkle it heavily with sesame seeds., Bake the braid for 25 to 35 minutes; the longer it bakes, the crunchier it'll be. When fully baked, the braid's internal temperature should measure at least 190°F on a digital thermometer., Remove the braid from the oven and cool it on a rack. For extra crispness, cool it in the turned-off oven with the door propped open., Store the braid in a paper bag for 24 hours; wrap in plastic and freeze for longer storage.