Mix the flour with 400g of the water and leave for 30 minutes to autolyse.
Mix the yeast with the remaining 40g water and work it into the dough. Add the salt, then the olive oil in a couple of stages, folding until fully incorporated.
Rest for 15 minutes, then stretch and fold. Rest another 15 minutes, then coil fold. Rest a final 15 minutes, then coil fold once more.
Cover and leave to rise until roughly doubled — about an hour, depending on how warm the room is.
Transfer to a well-oiled, parchment-lined tin. Fold the dough into thirds, rotate so the longer side runs lengthways along the tin, then flip so the seam sits underneath.
Cover and prove until doubled and filling the tin — around another hour.
Heat the oven to 230°C. Coat the dough generously with olive oil and dimple all the way down to the base of the tin. Rest for 15 minutes, then dimple again from the other direction, trying not to pop the bubbles that have formed.
Bake for 20 to 25 minutes, until deeply golden. Remove from the tin and cool on a wire rack. Finish with sea salt while still hot, and a final drizzle of extra virgin olive oil before serving.
This one's a mash-up of techniques from a few bakers I really rate on Instagram — @_lacebakes_, @lisakitahara and @henrymadefood — with a couple of my own tweaks. Go find their pages, they're all worth following.