Step 1: In a large mixing bowl, combine the bread flour, olive oil, salt, sugar, and active dry yeast. Add the warm water slowly while stirring until the dough comes together.
Step 2: Knead the dough on a lightly floured surface for about 5-7 minutes until it becomes smooth. Place the dough in a greased bowl, cover with a kitchen towel, and let it rest in a warm place for about 1 hour or until it doubles in size.
Step 3: While the dough is resting, prepare the toppings. Chop the onion and rosemary sprigs and set them aside.
Step 4: Once the dough has risen, gently punch it down and transfer it to a lightly floured surface. Roll the dough into a large rectangle shape about 1/2 inch thick.
Step 5: Sprinkle the chopped onion and rosemary over the top of the dough. Drizzle with a little bit of olive oil and sprinkle with coarse salt.
Step 6: Fold the dough in half lengthwise, then fold it in half again crosswise to create a zigzag pattern. Repeat this process two more times, folding the dough in half and then crossing it over itself.
Step 7: Place the dough into a greased 9x13 inch baking dish and dust with cornmeal. Cover with a kitchen towel and let it rise for about 30 minutes or until it has doubled in size again.
Step 8: Preheat your oven to 425°F (220°C). Once the dough has risen, remove the cover and use a sharp knife to make diagonal slashes across the top of the dough.
Step 9: Bake for about 25-30 minutes or until the bread is golden brown and sounds hollow when tapped on the bottom. Remove from the oven and let it cool for a few minutes before slicing and serving.
Enjoy your fresh rosemary and onion focaccia bread with your favorite toppings!