Mix and knead all of the dough ingredients — by hand, mixer, bread machine or food processor — until you've made a smooth, elastic dough., Place the dough in a lightly greased bowl, turn to coat, cover, and allow it to rise for 1 1/2 to 2 hours, or until puffy., Gently deflate the dough, and divide it into three equal pieces; each will weigh about 9 to 9 1/4 ounces. Roll each piece into a 20"-long rope, tapering the ends slightly., Place the ropes on a lightly greased or parchment lined baking sheet. Braid them loosely; pinch the ends together, and tuck them under., Brush the loaf with the beaten egg white, then cover the braid and let it rise for about 1 to 1 1/2 hours, or until it's quite puffy., While the bread is rising, preheat the oven to 400°F., Immediately before you put the loaf in the oven, brush it again with the egg white and sprinkle the sesame seeds or flax seeds on., Bake the braid for 20 to 25 minutes, until it's golden brown. (Tent it lightly with aluminum foil after 15 minutes, if it appears to be browning too quickly.), Remove the braid from the oven, and cool it on a wire rack., Store, wrapped, at room temperature for up to 5 days, or freeze for up to 3 months.