Kaiser Rolls

In a large bowl, dissolve yeast in 1/2 cup warm water. Add 1 tablespoon sugar; let stand for 5 minutes. Add the oil, salt, remaining warm water and sugar and 4 cups flour. Beat until smooth. Stir in enough remaining flour to form 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 top. Cover and let rise in a warm place until doubled, about 1 hour., Punch dough down. Turn onto a lightly floured surface; divide into 16 pieces. Shape each into a ball. Place 2 in. apart on greased baking sheets. Cover and let rise until doubled, about 30 minutes., Preheat oven to 400°. Beat egg white and cold water; brush over rolls. Sprinkle with poppy and/or sesame seeds. With scissors, cut a 1/4-in.-deep cross on tops of rolls. , Bake at 400° for 15-20 minutes or until golden brown. Remove from pans to wire racks to cool.