1. Chop the onion and garlic with the parsley and lamb meat.
2. Sauté this mixture in a tablespoon of olive oil over low heat, without letting it brown. If necessary, add a tablespoon of water.
3. Add the peeled, seeded, and quartered tomatoes. Season with salt and pepper, and add the white wine. Cover and simmer for 45 minutes.
4. Then, off the heat, add the crumbled stale bread crumbs and unbeaten egg whites (reserve the yolks for later). Mix well.
5. Peel the eggplants, slice them into rounds. Coat them in flour and sauté them in olive oil over medium heat (or fry for 3 minutes in a deep fryer). Drain them thoroughly on paper towels.
6. Butter a gratin dish. Layer in it: half of the eggplants, the meat mixture, and the remaining eggplants.
7. Sauce: in a saucepan, over low heat, melt 20 g of butter and add 2 tablespoons of flour (for 4 servings).
Whisk together, then add the cold milk all at once. Cook for 10 minutes, stirring constantly.
Off the heat, stir in the egg yolks and half of the grated cheese.
8. Pour this sauce over the dish. Season with salt and pepper.
Sprinkle with grated cheese.
9. Place the dish in a roasting pan with a little water. Bake for 45 minutes in a hot oven (thermostat 7 - 210°C).
Halfway through cooking, cover the surface with aluminum foil to prevent it from burning.
Can be unmolded before serving.