Place the flour, bicarbonate of soda and salt into a bowl, and gradually add the water. Mix until the dough becomes smooth, and then transfer to a kneading board. Knead for about 10 minutes until the dough becomes soft and elastic with a smooth, even surface.
Roll out the dough with a rolling pin, remembering to cover it with a light coating of flour, until you obtain a circular disc, 1 cm thick. Prick the dough with a fork to prevent bubbles from forming, and leave to cook on the stone griddle, heated over a low flame, for about 10 minutes each side. Cut into slices and serve while still hot.