1) Put a griddle pan over medium-high heat or preheat a gas or charcoal barbecue. Put an oven rack in the centre of the oven. Preheat the oven to 190°C/ gas mark 5. Butter a 20 by 30-cm glass baking dish.
2) Drizzle the aubergine slices, fennel slices and peppers with olive oil. Season with salt and pepper. Griddle the vegetables for 3 to 4 minutes each side until softened.
3) Spoon half of the marinara sauce over the bottom of the prepared baking dish. Arrange the aubergine slices on top. Sprinkle with a third of the mozzarella cheese and a third of a cup of Parmesan cheese. Arrange the peppers in a single layer on top. Spoon the other half of marinara sauce over the peppers. Sprinkle with another third of mozzarella cheese and one third Parmesan cheese. Arrange the fennel on top and cover with the remaining sauce. Sprinkle with the remaining cheese. Scatter the bread crumbs over the cheese and drizzle liberally with oil.
4) Bake until the top is golden and forms a crust, about 30 to 35 minutes
Remove from the oven and cool for 10 minutes before serving.
Cook's Note: The vegetables can also be baked at 190°C/ gas mark 5 for 15 to 20 minutes until softened.