For the zucchini and potato casserole, first grease a baking dish. Preheat the oven to 200 °C.
Melt the butter in a pan. Sauté the onion and garlic in it. Set aside.
Place half of the zucchini and potatoes in the baking dish, overlapping in layers. Sprinkle onion, garlic and herbs on top. Season with paprika powder, nutmeg, salt and pepper to taste. Place the second half of zucchini and potatoes on top and season again.
Place in the preheated oven for about 30 minutes. Then pour the whipped cream on top and finish baking for about 20-25 minutes.
Portion the zucchini and potato casserole and serve.