Mix the flours together and the baking soda with yoghurt and vinegar. Gradually, add the yoghurt with water to the flour mix along with the salt and oil. Knead the dough, you need to get a very thick consistency.
Put it into a greased tray and put it to bake in a heated oven. At the beginning, start off at 392°F (200 °C), then reduce the oven to 338°F (170 °C). Bake it slowly initially.
Allow it to cool and serve it, cut into pieces.