Combine flour, yeast, and salt in a bowl, keeping yeast and salt separate initially.

Add water (350ml) to the dry ingredients and mix using a claw-shaped hand motion.

Knead the dough on a floured surface, stretching and pulling until smooth and elastic.

Form the dough into a ball, place in an oiled bowl, and cover with clingfilm. Let it rise for 45-60 minutes, or until doubled in size.

Once the dough is smooth and stretchy, stretch it into a rough rectangle.

Chop the rosemary and drizzle with olive oil.

Sprinkle the rosemary mixture over both sides of the dough rectangle.

Fold one-third of the dough's length from one side and repeat on the other side.

Fold over the top and bottom of the dough.

Flip the dough over and stretch the surface, turning to tighten and seal the seams.

Place the dough onto a floured baking surface (thin metal pizza tray recommended).

Cover loosely with a towel or oiled clingfilm.

Preheat the oven to 220°F (104°C) with a metal tray on the bottom rack.

Let the dough rise for another 40-60 minutes, until light and airy.

Pour a cup of boiling water into the metal tray in the oven and quickly close the door.

Slash the surface of the dough with a sharp knife.

Sprinkle with sea salt and flour, then place the tray in the oven.

Bake for 25 minutes, then reduce the temperature to 180°F (82°C) and bake for another 15 minutes.

Allow the bread to cool for at least 30 minutes before slicing.