In a 4-qt. bowl, dissolve yeast and sugar in 1/2 cup water. Let stand 5 minutes. Add the butter, salt, remaining water and 3 cups flour. Beat until smooth. Stir in enough remaining flour to make a soft dough.
Turn onto a floured surface; knead until smooth and elastic, about 6-8 minutes. Place in a greased bowl, turning once to grease the top. Cover with plastic wrap and let rise in a warm place until doubled, about 1 hour.
Punch dough down. Divide into 2 parts. Shape into loaves. Place in greased 8x4-in. loaf pans. Cover and let rise until doubled, about 30 minutes.
Carefully brush tops with melted butter. Bake at 400° or until golden brown, about 35-40 minutes. Remove from pans and cool on a wire rack.