Slice the eggplants into large rounds about 5mm thick and brush liberally with olive oil then lay flat on the baking tray lined with baking parchment or a silicone baking mat. Bake for about 20mins, or until tender and brown, in an oven pre-heated to 180 degrees. Next, make your risotto. Bring the stock to a simmer and keep warm. Put the olive oil and half the butter in a heavy-based saucepan over a low heat, add the onion and garlic and sauté with a pinch of salt until a pale golden colour and translucent (about 15 minutes).
Add the tomatoes, basil, salt and pepper. Cook gently, uncovered, for 10 minutes until slightly thickened, then pour all but 1/2 cup of the mixture into a bowl and set aside. Add the rice to the tomato mixture in the pan. Increase the temperature to medium-high and stir for 2-3 minutes. Pour in the wine and cook, stirring, until it has nearly evaporated. Start adding the stock slowly a ladleful at the time, stirring continuously until the rice is about three-quarters cooked but still has a bit of ‘bite’.
Build your baked risotto in a rectangular roasting or baking dish or a cast iron casserole, greased, and in this order - a couple of tablespoons of tomato sauce, risotto, parmesan cheese, eggplant slices, tomato sauce and mozzarella. You should aim for two repeats and then finish with a top layer of rice, then parmesan cheese. The dish can be prepared ahead to the this point, refrigerated, then cooked when required, but it must be brought to room temperature before cooking.
Dot the top with butter and bake in an oven preheated to 180C for about 20-2 5 until it is crisp on the top and heated through. Allow to stand for 10 minutes before serving with a green salad and some garlic bread or similar.