Heat the raspberries in a saucepan with a little water. Stir in 2 tablespoons of sugar and dissolve. Let the raspberry mixture cool down a little. Mix the cornstarch with a little water until smooth and bring to the boil with the raspberries.
Meanwhile, whip the cream with the cream stiffener. Mix the low-fat quark with the eggnog, vanilla sugar and 2 tablespoons of sugar in a mixing bowl to form a smooth cream. Now fold in the cream.
Layer the quark and eggnog cream alternately with the raspberry mixture in tall dessert glasses. Chill for approx. 1 hour before consumption.