Mix all ingredients, apart from the olives and tomatoes, in a stand mixer fitted with the dough hook. Take care not to put the yeast in direct contact with the salt when they are first added to the bowl.
Knead well until the dough is elastic, smooth and shiny. Cover with a piece of cling film and leave to rise for one hour.
Divide the dough into two and add half of the olives and sun-dried tomatoes into each.
Shape both the doughs into rough round shapes and press firmly down. Sprinkle white flour lightly over the top and slash a cross in the tops using a very sharp, floured knife.
Place them on a baking sheet lined with parchment paper and prove for one hour in a warm place.
Bake at 425F for 30 minutes until golden-brown. Remove from the oven and cool on a wire rack.