Layers of fried aubergine, a properly simmered tomato sauce, mozzarella, and Parmesan, baked until the edges turn deep gold — Parmigiana is Southern Italy's most generous dish, built for a table full of people and rarely eaten in a hurry. The sauce is not an afterthought: a slow soffritto and a gentle simmer are what separate a real Parmigiana from a rushed one.
- Make the sauce first: sauté the finely chopped onion in olive oil over low heat until soft and translucent, but not browned.
- Add the tomato passata and half the basil leaves, torn by hand. Season with salt and pepper.
- Simmer gently, uncovered, for 10-15 minutes, stirring occasionally, until the sauce has thickened slightly and the raw tomato taste is gone.
- Meanwhile, slice the aubergines lengthwise and salt them for 30 minutes to draw out bitterness, then pat dry.
- Fry the aubergine slices in olive oil until golden on both sides, then drain on paper towels.
- Spread a thin layer of the sauce in a baking dish — just enough to cover, not drown the aubergine — then a layer of aubergine, mozzarella, Parmesan, and a few basil leaves.
- Repeat the layers, finishing with sauce, mozzarella, and Parmesan on top.
- Bake at 180°C for about 30 minutes, until bubbling and golden.
- Let it rest for 10 minutes before serving — it holds together much better once cooled slightly.