Stir together 2 1/2 cups water and yeast in a large bowl; let stand 5 minutes. Stir in salt and oil.
Add flour gradually, beating at medium speed with an electric mixer until a soft dough forms.
Turn dough out onto a floured surface; knead until smooth and elastic (4 to 6 minutes). Place in a lightly greased bowl, turning to grease top. Cover and let rise in a warm place (85°), free from drafts, 35 minutes or until doubled in bulk.
Punch dough down, and divide into 8 equal portions. Shape each portion into a 4-inch round loaf. Place loaves on lightly greased baking sheets sprinkled with cornmeal.
Cover and let rise in a warm place (85°), free from drafts, 35 minutes or until doubled in bulk.
Stir together egg white and 1 tablespoon water; brush over loaves.
Bake at 400° for 15 minutes. Brush with remaining egg mixture, and bake 10 to 15 more minutes or until golden. Cool on wire racks. Freeze up to 1 month, if desired.
Cut a 1/2-inch-thick slice from top of each loaf; scoop out centers, leaving 3/4-inch-thick shells. (Reserve centers for other uses.) Fill bread bowls with hot soup, and serve immediately.