Begin by mixing the biga. This is just another name for a pre-ferment or a starter, like a poolish. This helps the bread develop a slightly stronger flavour and helps with the texture. Combine the flour, water and yeast in a large bowl and stir until combined.
Cover with a layer of cling-film and leave to bubble away somewhere warm, but not too hot for around 12-16 hours.
When the Biga has doubled in size and the surface is covered in bubbles it's ready to use.
Place the Biga in the bowl of a stand mixer and add the rest of the dough ingredients. Make sure the salt and yeast do not touch as this can stop the yeast from working.
Attach the dough hook and mix on a very slow speed to begin with as the ingredients like to jump out of the bowl. When it is all starting to come together increase the speed to 6 if using a kitchenaid or medium if using another kind of mixer.
Continue to mix for around 6 minutes or until the dough is elastic and pulling away from the sides of the bowl and sticking to the dough hook.
Take another large bowl and oil it lightly with olive oil as this dough is really sticky.
Remove the dough from the dough hook and using a dough scraper, scrape the dough into the oiled bowl. Oil a piece of cling-film (just in case, it shouldn't get that big) and cover the bowl. Place it somewhere warm for 60-90 minutes or until it has doubled in size.
The dough should be very stretchy and sticky by this point.
Prepare a normal baking tray, around 25cm by 35cm 2-3cm deep, by greasing it with a teaspoon of olive oil and then dusting it lightly with a layer of type 00 flour.
Take the dough from the bowl using a dough scraper and drop it into the baking tray.
Using your fingers stretch the dough until it fills the whole tray.
Cover lightly with oiled cling film and leave to rise for another 30mins.
Mix together the warm water, oil and salt until it has emulsified.
After the bread has proven pour the water and oil mixture gently over the bread so it all stays in the pan.
Gently use your fingers to make indentations all over the dough to give it the signature focaccia look, pressing down the bottom of the tray, but not piercing the dough.
Leave to prove for another 30 mins.
Pre-heat your oven to 200C Fan and place a small bowl of water in the bottom of your oven, something like 100ml of water.
When the oven is hot the water will provide some much needed steam.
Sprinkle your with some flaky sea salt, how much is ip to you.
Bake it in the pre-heated oven for 20-25mins until golden. You don't want it too dark.
Also it comes out quite hard, just allow the bread to soften as it cools.
Serve in squares and sliced and filled with meat and cheese of cut into fingers and serve with balsamic vinegar and olive oil.