2: Process zucchini, potatoes and onion in a food processor or mandolin to make thin slices. You can also slice with a knife, but of course this will take longer. Set aside. Preheat your oven to 200°C (390°F).
8: Grate over 50 g Parmesan (Parmigiano Reggiano).
9: Bake for approximately 50 minutes at 200°C (390°F).
10: Enjoy hot or cold.
Remarks
You can replace the parmesan with another cheese, such as pecorino. Scarpaccia" means "old shoe" in Italian, but it's also a recipe with many variations: milk instead of water, extra eggs, zucchini on its own, and so on.