570 g Bread flour
10 g Kosher salt
3 tbsp Olive oil, extra-virgin
170 g Active starter
500 g Water
Nice, flaky sea salt, such as Maldon and rosemary for toping
Combine flour and water in a large bowl. Mix to form a lumpy dough. Cover and leave to rest for 30 minutes.
After 30 minutes, spread the starter over the dough in the bowl. Dimple it in and mix the dough as well as you can in the bowl. I find using my hand, shaped like a claw, with a kind of scooping motion towards the edge of the bowl helpful for this. Once mixed, sprinkle the salt and the reserved 15g (1 tbsp) of water over and mix this in in a similar fashion.
Cover and leave at room temperature for another 2 hours until doubled in size.
Drizzle half of the olive oil into a 9 x 13-inch baking tray or roasting dish (I prefer one with high sides but a rimmed baking sheet works). Gently tip the bowl over the tray and coax the dough out as carefully as possible - it should mostly fall out from its own weight. Oil your hands and flip the dough over so that both sides are now covered with a light layer of oil.
Chill the dough overnight (12-16 hours). 1 to 2 hours before you want to bake it, remove from the fridge and leave in a warm place to rise for a bit.
When ready to bake, preheat the oven to 220°C fan
Drizzle the remaining olive oil over the dough and use your fingertips to press down into the dough all over, making deep dimples for the oil to pool in. Sprinkle with some flakey salt, add any other toppings like rosemary sprigs, and bake for 20-25 minutes, rotating the tray halfway through the baking time to ensure an even bake. It should be golden all over with some more well-browned patches.