Sweat the onions in butter until translucent. Wash the zucchini, pat dry and rub in (small strips). Top up with a liter of vegetable stock. Add the sour cream and processed cheese. Peel and grate the potatoes and add them as well. Season to taste with salt, pepper, nutmeg and 1/2 teaspoon turmeric. Let everything simmer for about 20 minutes. Then serve.