First cook potatoes.
Remove seeds from zucchini, melanzani and cut into strips. Salt and let stand.
Fry the melanzani and zucchini strips until translucent. Then add finely chopped onion and garlic and saute. Season with salt, pepper and oregano.
Put the peeled tomatoes in a baking dish and spread the melanzani and zucchini mixture on top.
Cut the mozzarella into cubes and place on top. Grate the mountain cheese and sprinkle on top. Bake for 15 minutes at 180 °C.
Serve the casserole with the cooked potatoes.