Add the flour and baking powder to a large mixing bowl, and add a good pinch of salt and pepper. Roughly mix. Make a well in the centre, and pour in the olive oil and water. Use a spatula or wooden spoon to bring the mixture together into a rough, sticky dough.
When the dough has just come together, turn it out onto a clean, well-floured worktop.
Scatter a little more flour over the top, and use clean hands to start bringing the dough into a ball. Add a little more flour as needed to help the dough become less sticky and to stop it from sticking to the worktop. When the dough is less sticky, knead it for around 5-10 minutes.
Place the ball of dough in a lightly greased bowl, cover with a tea towel, and let it rest for 30 minutes.
Divide the dough into 6 equal pieces, and roll one of the pieces very thinly, dusting with more flour to stop it sticking to the worktop.
Place a large non-stick frying pan over a medium-high heat. When it's hot, pick up the rolled-out dough by rolling it over the rolling pin, and lay it in the pan. Prick all over with a fork to help prevent large bubbles. Cook for a few minutes, until the underside is slightly browned, then turn the piada over and cook the other side.
Remove the cooked piada from the pan, and repeat with the remaining balls of dough. Best eaten immediately, with your choice of fillings.