Place the water in the bowl of a stand mixer fitted with a dough hook. Add the flour and yeast and mix on a low speed for about 4 minutes, until it forms a dough.
With the mixer running, slowly drizzle in the olive oil. Keep mixing at a low speed for about 7 minutes. The dough will slide around at first and it will take a while to absorb all of the oil but it will get there eventually.
Turn the speed up to medium for about 3 minutes, then add the salt. Continue to mix on medium speed until the dough comes together and pulls away cleanly from the sides of the bowl. It will be quite a sticky dough but should be smooth and stretchy. Don't be tempted to add more flour.
Turn the dough out onto an unfloured surface and use a dough scraper to skim it across the surface, this will shape it into a ball with a shiny top. This technique can't really be explained well in writing, so I recommend buying Bertinet's course to learn properly! If in doubt, just use oiled hands to shape the dough into a ball.
Lightly oil a bowl and rub a little oil over the surface of the dough. Place the dough in the bowl, cover and set aside to rise for 1 ½ - 2 hours, until about doubled in size and full of big air bubbles.
Use a dough scraper to release the risen dough from the bowl onto an oiled surface. Use oiled hands to gently stretch it out into a rough rectangle. Flip the dough over onto an oiled approx 23 x 33 cm / 9 x 13 in baking/roasting tin.
Scatter over the sliced olives and arrange the halved tomatoes cut side up. Scatter with rosemary and thyme leaves and a few big pinches of dried oregano.
With oiled fingers, use your hands like claws to gently prod the toppings down into the dough.
Loosely cover and set aside to rise for 20-30 minutes until bubbly. Meanwhile, preheat the oven to 220°C/200°C fan/425°F/gas mark 7.
Drizzle the surface of the dough with a little more olive oil and dimple it again with your fingers, pressing all the way to the tray; this is what creates air pockets inside.
Sprinkle over a little flaky sea salt if you like, then bake for 20 minutes, until well browned. Transfer to a wire rack to cool and drizzle with a little more olive oil before serving if you like.