To make the dough in a food processor: Place the flours, yeast, and salt in the bowl of a food processor. In a jug, combine the water, yoghurt, and olive oil and mix well. Start the food processor. As it's running, pour the liquid ingredients into the shoot and let the food processor run for a bit, until everything is well mixed. Remove the dough from the food processor, knead a couple times to form a ball. Place the dough in a clean bowl.
To make the dough by hand: Mix the flours, yeast, salt, water and yoghurt in a bowl to form a sticky dough. If it seems really dry, and you’re having trouble working all the flour into the dough, add more water, a little bit at a time. Add the oil, mix it in. Knead until smooth and silky. Shape the dough into a round, then place in a clean bowl.
Leave the dough to rise, covered with cling film or a plastic bag, until doubled in size.
Deflate the dough, then if you have time, leave to rise a second, third, even a fourth time (this improves the dough but is by no means essential).
While all of this is happening. Get your fire going with some high quality hardwood. Let it roar. Wait for a good amount of wood to burn down into embers. This can take a couple hours so make sure you have something nice to drink and enjoy the fire while you wait!
Tear off pieces the size of small lemons (or smaller, or larger, if you like) one at a time, shape into a round, then using plenty of flour, roll out to a 3-4mm thickness.
Arrange your fire so that you have a nice pile of embers ... I usually create a pile of embers with the main fire burning next to it. Place the rolled dough directly on the coals. After a short while you'll see it start to bubble up. Before it goes really crazy, flip it over to cook the other side, removing any embers that may have stuck to the dough (see video). If all goes well your flatbread will puff up like a balloon! Remove the bread from the fire, brush with olive oil (this isn't essential but it sure is nice), and place in a teatowel while you make the remaining flatbreads. Keep stacking the flatbreads in the teatowel as you go which will keep the breads soft and warm.