In a large bowl, combine all-purpose flour, kosher salt, and instant yeast. Gradually stir in warm water and olive oil until a sticky dough forms. Cover and let rise for 1-2 hours until doubled.

Once risen, grease a 9x13-inch baking dish with olive oil. Stretch dough to fit the pan and cover with a towel for 30 minutes.

Heat olive oil in a small saucepan and add minced garlic. Sauté for 1-2 minutes until fragrant. Remove from heat.

Dimple the dough with fingers, drizzle garlic oil, and sprinkle with Parmesan cheese, rosemary, and flaky sea salt.

Preheat oven to 425°F. Bake for 20-25 minutes until golden brown.

Let focaccia cool in the pan for 10 minutes, then slice and serve warm.