Add yeast to 1/2 cup warm and let stand for 10 minutes.
Combine remaining water, sugar, salt, and butter Add 2 cups flour and mix well (you may use a mixer). Add egg and softened yeast to this mixture. Add remaining flour to make a soft dough. Turn onto a lightly floured surface and knead dough until smooth and satiny, 10 minutes by hand, or 4 minutes in an electric mixer or food processor fitted with dough hook. Put dough in greased bowl, turning to coat thoroughly. Cover with a damp towel and allow to rise in a warm, draft-free place until doubled, about 1 hour.
Knead dough down and turn out onto a lightly floured surface. Divide into 3 equal portions and let rest for 10 minutes. Grease three 9x5x3-inch loaf pans. Shape dough into loaves and put into pans, seam side down. Cover with damp cloth and allow to rise in a warm, draft free place until dough rises just above tops of pans, about 1 hour.
Preheat oven to 375°F.
Bake for 35-45 minutes, or until golden brown. Remove bread from pans immediately and let cool on racks.