1. Combine the water, yogurt, melted butter, salt, and sugar in a large bowl.

2. Stir in ½ cup of the flour and the yeast, then enough of the flour to make a soft dough. On a lightly floured work surface, knead the dough for 5 minutes, adding more flour as necessary, but keeping the dough soft, until the dough is smooth. During the last minute or so, knead in the onion seeds and shape into a ball.

3. Place the dough in a lightly oiled bowl and turn to coat with the oil. Cover with plastic wrap and let stand in a warm place until doubled in volume, about an hour.

4. Place two large baking sheets in the center and top third of the oven and preheat to 500°F (260°C). Knead the dough for a minute until smooth. Cut dough into 4 equal pieces and roll each into an oval about 10in (24cm) long.

5. Carefully transfer the breads to the baking sheets in the oven. Bake for 6 minutes, until puffed. Transfer to a wire rack. Position a broiler rack about 6in (15cm) from the heat and preheat the broiler. One at a time, broil the breads 30 seconds on each side until blistered and browned lightly. Serve warm.