Preheat your oven to 220°C (about 400°F).
Place the chopped eggplants on a baking tray lined with parchment paper.
Drizzle with two tablespoons of olive oil, season with salt and pepper, then mix.
Cook in the oven for twenty-five minutes or until they soften, then set aside.
Heat the remaining olive oil in a medium to large pan.
Add the garlic and cook until it becomes fragrant.
Add the crushed tomatoes, passata, milk, oregano, chili flakes, salt, ground black pepper, and bay leaf.
Cover with a lid, adjust heat to medium-low, and simmer for twenty minutes.
Start cooking the pasta as per package instructions --- then drain.
Taste the sauce and adjust the seasoning as desired.
Add the roasted eggplant, combine, and continue simmering for about five minutes.
Add pasta, mix, then add most of the Parmigiano cheese. (NOTE: Leave about two tablespoons for topping.) Combine everything evenly, then remove the pan from the heat.
Preheat oven to 200°C (375°F).
Transfer the prepared eggplant and pasta into a baking dish.
Sprinkle with the remaining grated Parmigiano cheese, and top with the mozzarella cheese.
Place in the oven for about thirty minutes or until it's golden.
Remove from the oven and set aside for at least fifteen minutes.
Your baked eggplant and pasta casserole is now ready for serving!