In a large bowl, add the flour and gradually add the water, whisking at the same time. Once all the water has been added, mix until completely smooth. Season with salt and pepper.
Let the mixture stand for 3 hours.
Heat oven to 180oC. Grease a large rectangle baking tray with the oil. Pour in the batter, making a layer about 1cm thick. Bake for 30 minutes, or until golden. Allow to cool before cutting and serving.