The evening before you want to bake, feed your starter to ensure it is very active and bubbly for the following morning.

The next day, weigh the water, sourdough starter and flour into a large bowl.

Mix well then cover and leave for 30 minutes to autolyse.
Next, add the salt and work well into the dough.

Place the dough back in the bowl, cover, and prove for 1 hour in a warm place.

Add half the olive oil and fold into the dough. To do this, imagine 4 sides. Fold the right side to the left, the left to the right, top to bottom, bottom to top.

Prove for another hour, then add the rest of the olive oil and repeat the folding process.

Leave to prove for one remaining hour with one further fold, taking care not to knock the bubbles out of the dough that are developing. The dough should be looking pillowy and bubbly. If it doesn’t, give it some more time.

Lightly oil a roasting tray with sides and gently pour the dough in. Drizzle with some more oil then gently stretch the dough to fill the tray. Leave for 30 minutes.

Stretch it out again if needed and sprinkle with a little flaked salt and the sliced onion. Prod holes deep into the dough using your fingers. You can make these pretty deep, as even though it is a flatbread, it will still rise due to the wild yeast.

Bake in a hot oven at 250°C for 20-30 minutes until baked through. Keep an eye on the dough, and if it is colouring too fast turn the oven down a little. Leave to cool on a wire rack.