Put the flour into a mixing bowl, then sprinkle the yeast on one side of the bowl and the measured sea salt on the other side. (The two cannot touch at this stage as they will counter each other, and your dough will not rise.) Cover each with a little flour. Make a well in the middle and add warm water and oil. Mix well with a table knife to incorporate the dough.
Transfer to a clean surface and knead until smooth. This will take around 4-6 minutes. Dust some flour to the board to eliminate sticking to it.
Brush the surface of the dough with a little olive oil and placed on a clean oiled bowl. Cover with saran wrap and let it rise in a warm place until it doubles in size, about 1 hour.
Grease a large baking tray. Scoop gently the dough from the bowl and place it onto the prepared baking tray. Flatten gently the dough to shape into a rectangle and spray or brush lightly with more oil. Cover with saran wrap, as before, and leave in a warm place for 30 minutes or until doubled in size.
Preheat the oven to 400F.
Slightly press the surface with your fingers to create small pockets. Sprinkle with fresh rosemary, abundant sea salt flakes. Drizzle with more olive oil.
Bake for 25 to 30 minutes, or until golden brown and cooked through. Transfer to a wire rack and leave to cool down slightly. Slice and serve warm.