Add 420g of the water to a large bowl. Tip in the yeast and flour and bring together with your hands until there are no dry lumps of flour left in the bowl.

Cover the bowl with cling film, or pop inside something airtight and leave for 1 hour to autolyse.

Once it’s had an hour or so, mix the remaining water with the olive oil and salt. Tip the mixture over your dough and use your hands to squash into the dough.

Turn the dough out onto a clean surface and give it a brief knead, it will be sticky but don’t worry.

Use a bench scraper to scoop the dough back up and into a clean bowl. Let it hang out for half an hour then give it a fold.

Dunk your hands into cold water or rub with olive oil, reach under the top side of the dough, grab it and stretch it up and out of the over the main body of the dough. Turn the dough 90° and repeat the fold again.

Complete four folds, one on each side. This counts as one turn. Leave the dough for another half an hour and fold again.

Let the dough rest for another 30 minutes before completing another turn.

Cover and place the dough into the fridge overnight for a long, slow proof.

When ready to bake, line a roughly 20x35cm baking tray with parchment and a glug of olive oil. Shape the dough into the lined tray and carefully encourage it to fill the tray.

Cover and leave to proof until the dough is super puffy again.

Preheat the oven to 230°C fan-assisted.

Strip the rosemary leaves from the stems and sprinkle all over the dough with a generous shower of flakey salt. Drizzle with olive oil and lightly wet your hands.

Use your fingers to dimple the dough all over, being careful not to overpress the dough.

Slide into the oven for 20-25 mins until golden brown and baked through.