Mix jelly powder and 100 g sugar in a saucepan. Add 500 ml water while stirring and mix well. Heat while stirring but do not boil until everything has dissolved. Pour approx. 2/3 of the jelly into a dessert bowl and chill for approx. 2 1/2 hours until the mixture begins to gel.
Leave the rest of the jelly in the pot at room temperature.
Sort 125 g raspberries. Spread the raspberries evenly over the dessert bowl. Pour the rest of the jelly from the pot over the raspberries and chill for another 2 1/2 hours.
Mix mascarpone, quark, vanilla sugar, 100 g sugar and lemon juice with the whisks of the hand mixer. Pour half of the cream onto the jelly and smooth
Spoon sponge cake horizontally, slightly raised, sit close together in the cream, press down gently. Sprinkle evenly with liqueur. Spread the rest of the cream loosely. Sort 125 g raspberries and spread on the cream.