Briefly bake the bread and divide lengthways (like a bread roll). Brush both halves with the tomato sauce as desired. Place the Parma ham on the bread halves, then cover lightly with a layer of rocket. Then put the sliced tomatoes on top. Season with salt and pepper.
Sprinkle the whole thing with the diced mozzarella and put it in the preheated oven (from baking) for about 10 minutes at top heat.
Finally garnish with the roughly plucked fresh basil.