Yield: 2 loaves.
1 cup warm water (100 to 110 F)
Place 1/2 cup warm water in large warm bowl. Sprinkle in yeast; stir until dissolved. Add remaining water, sugar, margarine, salt, and 1 1/2 cups flour; blend well. Stir in 3 eggs, 1 egg white (reserve 1 yolk), and enough remaining flour to make soft dough. Knead on lightly floured surface until smooth and elastic, about 6 to 8 minutes. Place in greased bowl, turning to grease top. Cover; let rise in warm, draft-free place until doubled in size, about 30 to 45 minutes.
Punch dough down. Remove dough to lightly floured surface; divide in half. Set aside 1 half. Divide remaining half into 2 pieces, one about 2/3 of the dough and the other about 1/3 of the dough. Divide larger piece into 3 equal pieces; roll to 12-inch ropes. Place ropes on greased baking sheet; braid. Pinch ends to seal. Divide remaining piece into 3 equal pieces. Roll to 10-inch ropes; braid. Place small braid on large braid. Pinch ends firmly to seal and secure to large braid. Repeat with remaining dough to make second loaf. Cover; let rise in warm, draft-free place until doubled in size, about 30 to 45 minutes.
Beat reserved egg yolk with 1 teaspoon water; brush over loaves. Sprinkle with poppy or sesame seed, if desired. Bake at 400 F for 20 to 25 minutes or until done, switching positions of sheets in oven halfway through baking time. Remove from sheets; let cool on wire racks.
Source: Fleischmann's Yeast, a division of Burns Philp Food, Inc.