Preheat oven to 220°C fan forced. Scatter the tomatoes in a roasting pan. Drizzle with both oil sachets and sprinkle with both salt sachets. Shake the pan to coat. Roast for 8 minutes until the tomatoes are tender and just start to collapse. Set aside to cool for 15 minutes. Reduce the oven to 180°C fan forced.
Meanwhile, mix butter, garlic, parsley and half the parmesan until well combined, season. Spread over the cut side of the rolls. Arrange garlic buttered side up on a greased 38cm round (or 30cm x 45cm) oven tray. Bake for 5 minutes until rolls start to colour. Remove from the oven.
Combine the mozzarella and cheddar and sprinkle 3/4 over the rolls. Top with salami, olives, tomatoes, remaining cheddar mix and remaining parmesan. Bake for 15 minutes until cheese has melted. Serve warm.