Mix water and yeast and let stand 15 minutes. Gradually pour in 2 cups of the flour mixture and incorporate. Mix for about 1 minute to form a sponge. Let stand, covered for at least an hour. Put sponge in the bowl of a Kitchen Aid. Using the dough hook, add the salt and oil, then flour 1/2 cup at a time to form a dough. Remove from bowl and knead. Place in a clean oiled bowl and let rise, slowly, about 2 1/2 hours. Divide dough into three balls, let rise again for 1/2 hour and roll out.
