Wash and clean the rhubarb, cut in half lengthwise and cut into pieces about 1 cm wide. Boil 150 ml water with syrup and 25 g sugar. Add the rhubarb and cook for about 1 minute. Pour the rhubarb through a sieve, collecting the stock. Set aside approx. 4 tbsp. brew. Pour the rest of the brew back into the pot and bring to the boil again. Stir starch with 2 tbsp. cold water until smooth. Bind the brew with it. Cook for about 2 minutes, stirring continuously. Add the rhubarb to the stock again, stir and place in a flat, slightly larger container, allow to cool and chill for about 15 minutes
Stir mascarpone until smooth. Separate eggs. Beat the egg yolks and 75 g sugar with the whisk of the hand mixer for approx. 4 minutes and fold into the mascarpone. Beat the egg whites until stiff and finally add vanilla sugar. Carefully fold the egg whites into the mascarpone mixture
Cut the biscuits in half. Fill half of the cream into a piping bag and distribute in 4 glasses (500 ml??). Place 2 half sponge cakes on the cream, sprinkle with the brew and distribute the compote on the sponge cakes, up to 4 tsp. Pour the rest of the cream onto the compote. Sprinkle with cocoa, add 1 tsp. compote and decorate with chocolate rolls.
Waiting time approx. 15 minutes