I slice the eggplants lengthwise about 5 mm thick and arrange them on a baking sheet lined with parchment. Spritz with olive oil, season, and roast until tender. They look dry but will be wonderfully soft once baked in the casserole.
In a bowl, I mix tomato passata with fresh oregano and basil. This simple sauce brings out the summer flavors and complements the creamy cheese beautifully.
I whisk together ricotta, 1 cup parmesan, eggs, and remaining oregano. This creamy layer adds richness and binds the casserole layers together perfectly.
In the baking dish, I layer eggplant, sauce, and cheese mixture, repeating until all ingredients are used. I finish with the remaining parmesan on top for a golden, cheesy crust.
I bake the casserole at 430°F (220°C) for about 30 minutes until the top is golden brown. Ovens vary, so I keep a close eye to prevent over-browning. After baking, I let it rest a few minutes before slicing.