Preheat the oven to 180ºC, fan 160ºC, gas 4. Brush the aubergine slices all over with 2 tablespoons of the oil. Arrange in a single layer on a large baking tray and bake for 10 minutes.
Meanwhile, heat the remaining oil in a pan, add the garlic and cook for 2 minutes. Stir in the chopped tomatoes, tomato sauce, basil and some freshly ground black pepper. Simmer for 10-12 minutes until thickened.
Spoon a little of the sauce into a 1.5 litre oven proof dish. Add a layer of aubergine slices then top with some mozzarella. Repeat until everything is used up. Sprinkle with the hard cheese; bake for 20 minutes.
Garnish with the extra basil and serve with the bread and salad on the side.