In a large bowl, whisk together flour, yeast, and salt.
Add warm water and 0.25 cup olive oil. Mix until a shaggy dough forms.
Turn dough out onto a floured surface and knead for 8-10 minutes until smooth and elastic. Or, use a stand mixer with a dough hook for 5-7 minutes.
Place dough in a lightly oiled bowl, turning to coat. Cover and let rise in a warm place for 1-1.5 hours, or until doubled in size.
While the dough is rising, prepare the topping. In a small bowl, whisk together 0.25 cup olive oil, minced garlic, Parmesan cheese, rosemary, salt, and pepper.
Preheat oven to 425°F (220°C). Grease a 9x13 inch baking pan.
Punch down the risen dough and press it into the prepared baking pan. Make dimples in the dough with your fingertips.
Drizzle the garlic Parmesan mixture evenly over the dough, pressing it into the dimples.
Bake for 25-30 minutes, or until golden brown and cooked through.
Let cool slightly before slicing and serving.
Notes
Enjoy this focaccia warm or at room temperature. It's great on its own or served with soups and salads.