Preheat the oven to 220 °C. Rinse and clean the zucchini, grate into fine sticks and place in a shallow gratin dish.
Rinse and clean the spring onions or leeks and cut them into tender strips. Peel and rinse the potatoes and grate them onto the zucchini. Mix onions, potatoes and zucchini and season with salt.
Grate or finely dice the cheese and stir in. Pour the whipped cream over it. Sprinkle with pine nuts or breadcrumbs.
Place the dish on the middle shelf of the oven and bake the gratin for 25-half hours.
In addition to feta cheese, mix in some leftover mozzarella. Baking time 45 min. Very good, zucchini stay nice and crisp.
Tip: The flesh of young, small zucchini is much more tender than that of larger.