Briefly mix the quark and liquid cream in a mixing bowl with a whisk. Then simply fill up with the buttermilk and season with vanilla sugar and normal sugar, depending on your taste, and stir well.
Put the cold bowl in the refrigerator for about an hour. Whip again briefly before serving. Add chopped fruit such as bananas, strawberries or pears - but the buttermilk soup tastes delicious even without fruit 😉