Turn the dough out onto a lightly floured work surface. Pull off about a quarter of it — you'll use this to form the braids. Shape the remaining large piece of dough into a smooth ball, and place in the center of the prepared pan.
04Divide the reserved piece of dough into three equal pieces, and roll each one out into a strand about 18"-20". Use these three strands to create one long braid. (See photos in post for a visual.)
05Cut the braid in half, then place in a cross on top of the larger piece of dough in the pan. (Alternatively, you could wrap the braid in one length around the inside edge of the pan.)
06Cover the loaf and let rise for about 45 minutes, until approximately doubled in size. Near the end of the rising time, preheat the oven to 350 degrees F (180 C) and place a rack in the lower-middle.
07When the bread has risen, make the topping. Beat the egg and water together with a fork in a small bowl, and brush the mixture gently over the loaf. Sprinkle with additional sugar, as desired.
08Bake bread for 35 to 45 minutes, until the top is a rich golden brown. Remove from the oven and let cool completely before cutting and serving.