In the bowl of a stand mixer fitted with the dough hook, mix the All-Purpose Flour (3 3/4 cup) and Salt (2 teaspoon) together to blend them. In another bowl, pour the Active Dry Yeast (1 package) into the Water (2 cup), then gently whisk in the Olive Oil (3 tablespoon).
Slowly pour those wet ingredients into the stand mixer bowl of dry ingredients with the dough hook running until a sticky dough forms. Cover the stand mixer bowl with plastic wrap and let the bread dough double in size for about an hour in a warm area of the kitchen.
Once the dough has doubled in size, take a half sheet pan and grease it liberally with olive oil using your clean hands. Use your oiled hands to turn the dough out on to the sheet pan and gently spread it out to pretty much fill the bottom. Use your fingers to poke holes evenly in rows throughout the dough for the signature focaccia bread look and texture.
Sprinkle the Parmesan Cheese (1/4 cup) and Rosemary Leaves (1 sprig) evenly on top. Cover the sheet pan and allow the dough to ferment again for another 40 minutes. It will puff up even more.
Preheat the oven to 450 degrees F (230 degrees C).
When the dough is almost done with its second round of proofing. Remove the cover from the sheet pan and sprinkle extra parmesan cheese on top of the focaccia bread. Bake the bread for about 20 minutes, until it is golden and puffy.
When it is done, take it out and let it cool. Then just cut it into the desired sized pieces and serve immediately! Whatever is not used immediately can be frozen and kept for a couple of weeks. Enjoy!