In ancient times, this flatbread was cooked on a griddle, known as a testo or panaro - simply a flat, roughly circular stone. It is only recently that a circular, oven-fired clay and marble base has been used instead. It is left over the heat until it becomes piping hot, and is then used to prepare the traditional dough.
The simplicity of this flatbread is the perfect embodiment of Umbrian cuisine. An open fire provides a regular heat source and allows for the preparation of grilled or spit-roasted meats and vegetables to accompany the classic torta al testo.
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.