Add the salt and the whole wheat flour. Add the rest of the all-purpose flour, 1/2 cup at a time, until the dough is pulling away from the sides of the bowl. Turn the dough out onto a lightly floured counter and knead it, adding more flour as necessary, until the dough has formed a smooth ball. Place the dough in an oiled bowl and turn the dough to coat it with the oil. Cover the bowl with plastic wrap or a damp towel. Let the dough rise in a draft-free place for 1 1/2 to 2 hours.
NOTES : The combination of Italian frittata and focaccia is perfect for a summer evening.