Whisk together flour, yeast, salt, and sugar.
Add water and yogurt, and mix into a soft dough.
Knead the dough for 10 minutes, until smooth, adding more flour if it gets sticky.
Let dough rest for 5 minutes.
Roll dough out to a thickness of about ¾ inch.
Cut out 12 circles with a 3 inch round cutter.
Re-roll any excess and form more muffins. You should get 12-16 muffins total.
Sprinkle a baking sheet with semolina, and cover each side of muffins with it.
Cover with a damp towel and let rise in a warm place for about an hour, until almost doubled in size.
Heat a flat griddle pan until hot and brush with oil.
Add the muffins and reduce heat to medium.
Cook for 12 minutes, six minutes on each side, until firm and golden brown. Turn only once.
Serve with butter and jam.