In a large mixing bowl, combine the 1/2 cup warm water and yeast. Let stand for 5 to 10 minutes or until yeast dissolves and mixture is bubbly on top.
Stir the remaining 2 cups of warm water, the sugar, orange flower water (if you like), oil, and salt into the yeast mixture. Add 3 cups of the flour. Beat with an electric mixer on low speed for 30 seconds, scraping sides of bowl constantly. Beat on high speed for 3 minutes. Stir in as much of the remaining flour as you can with a wooden spoon.
Turn out onto a lightly floured surface and knead in enough of the remaining unbleached flour to make a moderately soft dough thats smooth and elastic (about 3 to 5 minutes total).
Shape the dough into a ball. Place dough in a lightly greased bowl; turn once to grease surface of the dough. Cover and let rise in a warm place until doubled in size (about 1 hour).
Punch the bread dough down and turn it out onto a lightly floured surface. Divide the bread dough in half. Cover the dough and let rest for 10 minutes. Roll each portion of the bread dough into a 9x4-inch rectangle. Place each loaf on a greased large baking sheet. Make three or four 3-inch-long diagonal cuts completely through each rectangle to within 1 inch of the edges. Slightly stretch the bread dough to widen and open the slits.
Cover the loaves of unbaked bread and let rice in a warm place until nearly doubled (30 to 40 minutes).
Beat together the beaten egg and the 1 tablespoon water. Brush the top of the loaf-shaped dough with the egg mixture. Sprinkle with pearl sugar.
Bake in a 375 degree F oven for 20 to 25 minutes or until bread sounds hollow when lightly tapped. (Cover loosely with foil during the last 5 to 8 minutes of baking to prevent overbrowning, if needed.) Immediately remove the loaves from the baking sheets. Cool loaves on wire racks.
Orange flower water is available in most Asian markets or specialty bake shops. Pearl sugar is sold at specialty bakeries.