1. Rub the butter into the flour and sugar.
2. Add the raisins and mix well.
3. Slowly stir in enough yogurt to mix to a fairly stiff dough.
4. Turn the mixture onto a floured board and knead lightly.
5. Roll out the dough to about 2cm/ 3/4 -inch thick and cut into 5cm/2-inch rounds.
6. Place on a lightly greased baking tray and bake, near the top of the oven, at 220°C/425°F/Gas Mark 7 for 14-16 minutes.
7. Remove from the tray and cool on a wire rack. Serve warm.