Combine flour, baking powder and salt in a large bowl and make a well in the centre. Pour oil and orange juice into the well, then mix to form a smooth, satiny dough. Cover dough with plastic wrap and leave to rest for 30 minutes while preparing the filling. Preheat the oven to 180°C.
For the olive filling.
Combine all the filling ingredients in a bowl and mix well, then divide in half.
For the egg-yolk glaze.
Divide the rested dough into 2 equal portions then roll out each portion into a rectangle measuring 20cm x 24cm. Scatter each rectangle with half of the olive mixture to evenly cover pastry. Roll up to form a log. Transfer the logs to a baking tray pre-lined with non-stick baking paper and lightly brush each roll with the egg-yolk glaze. Bake for 35-40 minutes or until golden brown. Remove to wire rack to cool. Once cold, slice into 1cm-thick rounds and serve. Makes 36.