In a food processor, combine the flour, whole wheat flour, yeast and salt. Add the warm water and the olive oil. Process until it forms somewhat of a dough ball. (If too dry, add some more water and if too wet, add more flour but it should be okay without adding more flour or water).
Transfer the dough into a large bowl. With floured hands, knead the dough by hand several times. Then incorporate the olives and the rosemary(and the lemon zest if using). This part is a bit messy but keep kneading. The olives and the rosemary will be eventually incorporated.
Form the dough into a ball. Cover the bowl with plastic wrap. Let the dough rise for up to 2 hours until it doubled in size.
Punch the risen dough down and knead a few times. Form into a ball with the seam on the bottom. Place on a well-floured baking sheet. Sprinkle flour all over the bread loaf. Slash the top of the bread with a sharp knife or razor blade in whatever pattern you like. Cover with a towel, and let it rise again until it doubled in size.
In the meantime preheat the oven to 425°F / 220°C When the bread has doubled in size, transfer the baking sheet into the preheated oven. Bake the bread for about 15 minutes at 425°F / 220°C Then turn down the heat to 375°F / 175°C and bake for 40 to 60 minutes until golden brown. Let it cool.