Dissolve yeast in warm water in warmed bowl.
Add salt, butter and flour.
Attach bowl and dough hook.
Turn to Speed 2 and mix until well blended, about 1 minute.
Knead on Speed 2 for 2 minutes.
Dough will be sticky.
Place in a greased bowl, turning to grease top.
Cover; let rise in warm place, free from draft, until doubled in bulk, about 1 hour.
Punch dough down and divide in half.
Roll each half into a 12 x 15-inch rectangle.
Roll dough tightly from longest side, tapering ends if desired.
Place loaves on greased baking sheets which have been dusted with cornmeal.
Cover; let rise in warm place, free from draft, until doubled in bulk, about 1 hour.
With sharp knife, make 4 diagonal cuts on top of each loaf.
Bake at 450° for 25 minutes.
Remove from oven.
Beat egg white and water together with a fork.
Brush each loaf with mixture.
Return to oven and bake 5 minutes longer.
Remove from baking sheets and cool on wire racks.