Preheat the oven to 140C/275F/Gas 1.
In a small bowl, mix the yeast with one tablespoon of warm water. Stir in the sugar and leave it in a warm place for five minutes until the yeast is covered with froth.
Meanwhile, mix together the flour, onion seeds, salt and baking powder. Stir in the oil, yoghurt and milk, then stir in the activated yeast mixture.
To knead the dough, clench your hand into a fist, wet your knuckles with a little water, then press them repeatedly into the dough. Continue pressing and kneading until you have a soft, pliable dough. It should take about 10 minutes.
Place the dough in a mixing bowl, cover it with cling film and leave it in a warm place to rise for 10-15 minutes.
Divide the dough into four balls and place on a floured surface or board. Roll each into a long oval shape about 0.5cm (¼ inch) thick. Don't roll them out too thinly or they'll turn out like crisps.
Place them on a greased baking tray and put them in the centre of the oven for 10-15 minutes. They are ready when they have puffed up a little. They should be soft and crumbly, not chewy. Serve fresh from the oven.