Activate the Yeast: In a small measuring cup, combine 1 ⅓ cups lukewarm water (between 90°F and 110°F) with the yeast and sugar. Whisk, cover with a clean kitchen towel and leave somewhere warm for 15 minutes to activate the yeast.
Make the Dough: In a large mixing bowl, whisk together the flour, olive oil, and salt. Stir to combine, then make a well in the center. Add the yeast mixture and stir to form a shaggy dough.
Knead the Dough: Sprinkle a little flour onto a clean surface and lay the dough on the flour. Knead for 5-10 minutes, or until the dough becomes smooth and silky. Place dough into a clean, oiled bowl. Cover with plastic wrap and leave in a warm, dark place for 1 hour, or until it has doubled in size.
Prepare the Glaze: Place a small saucepan on medium-high heat. Add the water, flour, baking powder, and olive oil 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.
Knock Back and Divide the Dough: Once the dough has risen, place the dough onto a floured surface. Punch into the center of the dough, then gently pinch the dough at the edges, pull into the center and push down until the large air pockets have escaped. Divide the dough into two even halves.
Shape the Barbari: Use a floured rolling pin to roll one half into an oblong shape, then hand-stretch it until it’s about 11-inches long and 8-inches wide. Place the shaped half on a parchment-lined baking tray. Use a sharp knife and lightly score along the length of the dough, about a finger-width apart. Use your fingers to push the dough down between the scored lines so you end up with small ridges, being careful not to push all the way through. Repeat with the remaining half of the dough and leave the bread to proof a second time for 30 minutes in a warm, and dark place.
Preheat Oven: Preheat the oven to 425°F.
Glaze, Top and Bake the Barbari: Preheat your oven to 425°F. Brush each of the Barbari breads with the glaze. Use your fingers to define the ridges in the bread again, then top with sesame and nigella seeds. Bake until your barabari bread is golden, about 20 minutes.
If your yeast isn’t bubbly after activating it in water, let sit for another 10-15 minutes and check on it again. If it’s still not foamy, your yeast might be bad, in which case the best option is to buy some new yeast at the store and try again.
To check the rise of your bread, you can use a piece of masking tape on the outside of your mixing bowl to mark the top of your bread before proofing.