Sprinkle yeast into warm milk in a bowl. Leave for 5 minutes; stir to dissolve. Mix flour and salt in another large bowl. Make a well in the centre and add dissolved yeast, sugar, yogurt and melted butter. Mix in flour to form a stiff, sticky dough. Add a little more flour if required. Turn dough out onto a lightly floured work surface and knead until smooth, stiff, and elastic, about 10 minutes. Put dough in a bowl and cover with a cloth or dishtowel. Let rise until doubled in size, about 3 ½ hours. Punch down.

Divide dough into eight equal pieces. On a lightly floured work surface, roll out each piece to form a round, 6 inch (15 cm) across and ¼ inch (5 mm) thick. Pull one side to form a tear shape; stretch the dough until about 10 inches (15 cm) in length. Preheat grill on the highest setting. Preheat a baking sheet under the grill for about 2 minutes. Place a piece of dough on hot baking sheet. Grill the dough for about 2-3 minutes on each side, until puffy and golden. Stack grilled breads on top of one another and cover with a clean, dry cloth to keep the crusts soft and to prevent drying out.