Preheat oven to 180ºC. Place the butter, sugar and vanilla in the bowl of an electric mixer and beat until pale and creamy. Gradually add the eggs and beat well. Add the flour and baking powder and beat until a smooth dough forms. Fold through the chocolate. Roll 2 tablespoonfuls of the mixture into balls, place on baking trays lined with non-stick baking paper and press to flatten. Bake for 12–15 minutes or until golden. Allow to cool on the trays. Makes 12.