For the gratinated zucchini, sauté onion in oil. Add minced meat and fry until white.
Then pour chopped tomatoes or strained tomatoes and simmer. Season with tomato paste, salt and pepper.
Wash and hollow out the zucchini and fill with the mixture.
Grease a mold with butter and put the zucchini in it. Sprinkle the zucchini with cheese and bake for about 30 minutes at 180 °C.
Arrange the baked zucchini and serve.