In a large mixing bowl, combine flour, kosher salt, and instant yeast.

Add lukewarm water to the dry ingredients and mix until a shaggy dough forms.

Drizzle 2 tablespoons of olive oil over the dough. Cover the bowl with plastic wrap and let it rest at room temperature for about 1 hour or until doubled in size.

After the dough has risen, use the remaining 2 tablespoons of olive oil to grease a 9x13 inch baking pan.

Transfer the dough to the greased pan, spreading it out evenly. Cover and let it rise for another 30 minutes.

Preheat your oven to 425°F.

Use your fingers to dimple the dough, creating small indentations. Sprinkle chopped rosemary and flaky sea salt over the top.

Bake in the preheated oven for 20-25 minutes, or until golden brown and cooked through.

Remove from the oven and let cool slightly before slicing and serving.