Place the ladyfingers in a mold, a baking dish is very suitable, and soak them with about 50 ml of the champagne-syrup mixture. Let it steep for 1 hour.
Soak and prepare the gelatine according to the instructions on the packet. Mix the quark with the sifted powdered sugar. Stir in the remaining sparkling wine and lime juice. Then stir in the gelatine. Whip the cream until stiff and add it to the lightly gelled quark mixture.
Spread the quark cream on the biscuits and chill for at least 3 hours. Mix the chopped mint with the cane sugar and sprinkle over the tiramisu just before serving.