For the Barbari dough - Use 150 ml of the water and pour into a bowl. Add the sugar and yeast, stir and leave to work for approximately 15 mins (bubbles will form on the surface).
Place the flour in a large bowl, add the oil and then add the salt to one side of the bowl.
Add the yeast mixture to the bowl and begin mixing the ingredients together. Gradually add the remaining water (200 ml) until all the flour leaves the side of the bowl and you have a soft, rough sticky dough.
Sprinkle a bit of flour onto a clean surface and sit the dough on the flour and begin to knead. Do this for 5-10 minutes, or until the dough becomes smooth and silky - it will be a little stickier than your standard loaf dough. Once the correct consistency is achieved, place the dough into a clean, oiled bowl. Cover with cling film and leave in a warm place for 2 hrs or until it has tripled in size.
To make the glaze - place a small saucepan on a medium / high heat and add 100 ml of water, 1 tsp of flour, 1/2 tsp of baking powder and stir until it forms a shiny white paste. Remove from the heat and set aside until you are ready to glaze prior to baking.
Once risen, place the dough onto a floured surface. Knock back the dough a few times to remove the air but no need to knead again.
Halve the dough and take one half and begin to shape it. I use a floured rolling pin to roll the dough into an oblong shape and then hand-stretch it until it gets to approximately 40 cm in length, 20 cm in width and 1 cm in depth. Place it on a grease-proof paper lined baking tray. Then take a knife and lightly score along the length of the dough about a finger-width apart.
Repeat the step above with the remaining half of the dough.
Cover the baking trays with tea-towels and leave in a warm place for 30 mins.
Pre-heat the oven to 200°C (fan) / 220°C (conventional) / Gas Mark 7.
Take a baking tray containing one of the Barbari breads and brush with the glaze. Use your fingers to push the dough between the scored lines down so you end up with small ridges. Then top with sesame and nigella seeds. Repeat with the other Barbari bread.
Place the bread in the oven. Bake for 20 minutes until golden and cooked. I slice mine into squares so they can be easily toasted for breakfast.