PREHEAT AN OVEN to 350°F (Gas Mark 4). Prepare a pastry case and blind-bake it. Slice the aubergines into rounds, about 10 mm thick, brush both sides of the slices with olive oil and roast them on an oven tray, until lightly browned and cooked through. Slice the tomatoes the same thickness and remove the seeds. Roast them in the same way. Place a layer of slightly overlapping aubergine slices in the bottom of the pastry case. Arrange a layer of tomatoes on top, sprinkle with salt, pepper and some torn basil leaves, then put in a layer of mozzarella slices. Sprinkle a little grated parmesan over this. Whisk the eggs and cream together and pour half of this custard over the vegetables. Put in another layer of aubergine, some more basil, a layer of tomatoes on top, and a final sprinkling of seasoning and parmesan. Now pour in as much of the remaining custard as the tart will take - it should take it all. Carefully place the tart in the oven and bake it for 30-40 minutes, until the custard has just set. The tart will firm up perfectly if you leave it to rest for five to ten minutes before you slice it, and it will also taste better for being a good few degrees down from oven-hot.