Make sure your starter is active – it should be nice and bubbly. If it isn’t, feed it and wait until a teaspoon of the starter floats in warm water. When you’re happy your starter is active, measure 100g into a large bowl and pour over 400ml tepid water. Stir with a rubber spatula to combine, but don’t worry if there are unmixed bits of starter. Tip in the flour and mix everything together to make a rough dough. Make sure all the flour is mixed in and that there are no dry bits up the side of the bowl. Cover and leave to rest for at least 30 mins or up to 1 hr.

Prepare a jug of water for dipping your hands into. Scatter 10g salt over the dough, dip a hand into the water and scrunch it through the dough to mix in the salt. The dough should come back together and the salt should be completely mixed in. Cover again and leave for 20-30 mins, then wet your hands, grab the dough from one side and stretch it over itself. Repeat with the other side of the dough – it should be very elastic. Curl the dough around onto itself so it’s smooth and taught, then cover and leave for another 20-30 mins. Repeat this process two more times (three in total), then leave the dough to prove for 2-3 hrs until risen by about 40 per cent – it should be bubbly and soft.

Drizzle a deep, roughly 20 x 30cm baking tray with half the olive oil and scrape the dough onto the tray. Incorporate the oil into the dough by stretching and folding it on the tray until it comes together. Don’t worry if it's a bit stringy to start, just keep stretching and bringing it back on itself and it will come back together. When the dough has come together into an oily mass, leave to prove at room temperature for 3-4 hrs, or for up to 18 hrs in the fridge.

Heat the oven to 220C/200C fan/gas 7. Use your fingers to stretch the dough so it fits into the tray evenly, then dimple the surface with your fingertips. Drizzle with 1 tbsp olive oil and dimple a few more times to create little oil puddles on the surface. Scatter over the remaining salt, give the dough a final poke and bake for 25-30 mins until puffed up and deep golden. Remove the tray from the oven, drizzle with the remaining oil then leave to cool for at least 40 mins before cutting into squares.