Arrange the zucchini slices in a tray on absorbent paper and sprinkle with a teaspoon of salt. Let rest for about an hour to get as much water out as possible. Pat the zucchini slices dry with paper towels to remove excess moisture.

Heat a tablespoon of olive oil in a saucepan, add chopped onion, and fry over medium heat for a few minutes.

Add meat and cook over medium heat for 2–3 minutes.

Then add the tomato sauce, half a teaspoon of salt, and pepper to taste, and simmer for 10 minutes, or until the water has evaporated, and the sauce is thick.

Meanwhile, in a bowl combine ricotta, eggs, nutmeg and a teaspoon salt, until you obtain a smooth cream.

Layer the zucchini in a 22×22 cm baking pan: zucchini, half meat, half ricotta cream, half the mozzarella, then more zucchini, the remaining meat, the remaining ricotta cream, and the remaining mozzarella. Finish with Parmesan.

Cover with aluminum foil and bake at 180 °C for 30 minutes. Remove the foil and bake until the lasagna is golden brown, about 30 more minutes (total time varies significantly by oven type).

Remove from oven, and let rest for 10 minutes before serving!