Combine 1 cup flour, milk, undissolved yeast and salt in a large bowl. Heat water, yogurt and oil until very warm (120° to 130°F). Gradually add to flour mixture. Beat 2 minutes at medium speed of electric mixer, scraping bowl occasionally. Stir in enough remaining flour to make a soft dough. Knead on lightly floured surface until smooth and elastic, about 8 to 10 minutes. Cover; let rest 10 minutes.Divide dough in half; roll to 15 x 10-inch rectangle. Beginning at short end of each rectangle, roll up tightly as for jelly roll. Pinch seams and ends to seal. Place on greased baking sheet. Cover; let rise in warm, draft-free place until doubled in size, about 1 hour.
Brush loaves with egg white; sprinkle with cornmeal. With sharp knife, make slashes, 1/4-inch deep across top of each loaf. Bake at 400°F for 25 to 30 minutes or until done. Remove from sheet; cool on wire rack.