In a large bowl, whisk together the flour, instant yeast, and salt.
Add the warm water and 2 tablespoons of olive oil. Stir with a wooden spoon until a sticky dough forms.
Cover the bowl with a clean kitchen towel and let rise in a warm place for 1 hour, or until doubled in size.
Preheat the oven to 425°F (220°C). Generously grease a 9x13-inch baking sheet with olive oil.
Transfer the dough to the prepared baking sheet. With oiled hands, gently stretch the dough to fit the pan. If it springs back, let it rest for 10 minutes, then continue.
Dimple the dough all over with your fingers. Drizzle with additional olive oil and sprinkle with chopped rosemary and coarse sea salt.
Bake for 20-25 minutes, until golden brown and crisp around the edges. Let cool slightly in the pan before slicing.