1.Preheat the oven to 220°C (200°C fan-forced). Grease a 23cm square cake pan.
2.Sift the flour and salt into a large bowl. Using your fingertips, rub in the butter until mixture resembles coarse breadcrumbs; add the finely chopped rosemary and halved olives. Stir in the buttermilk and enough of the water to make a soft, sticky dough.
3.Knead dough on a floured surface until smooth; using your hands, press the dough into a 22cm-square shape. Using a sharp knife, cut the dough into 12 equal pieces; place pieces slightly apart in the pan.
4.Brush tops with the extra buttermilk; top with the extra rosemary sprigs and olives.
5.Bake for about 30 minutes or until golden brown. Stand in pan for 5 minutes before turning out.