Coarsely grind rusks in the universal chopper. Melt butter. Mix butter and rusk. Put the crumbs on the bottom of a springform pan (26 cm Ø), press them down and put them in a cool place. In the meantime soak gelatine in cold water.
Cut the vanilla pod lengthwise and scrape out the pulp. Mix yoghurt, sugar, vanillin sugar, vanilla pulp, lime zest and juice. Squeeze the gelatine and dissolve. Mix with 2 tablespoons of the yoghurt mass, stir into the yoghurt mass drop by drop and chill for 10-15 minutes. In the meantime, whip the cream until stiff. As soon as the mixture begins to gel, fold in the whipped cream, place on the crumb base and smooth it down. Chill for at least 2 hours. Carefully remove the cake from the edge of the springform pan with a knife. Peel the kiwis and cut into thin slices. Sprinkle the kiwi slices with sugar syrup.
As soon as the mixture begins to gel, fold in the whipped cream, place on the crumb base and smooth it down. Chill for at least 2 hours. Carefully remove the cake from the edge of the springform pan with a knife. Peel the kiwis and cut into thin slices. Sprinkle the kiwi slices with sugar syrup. Place the kiwi slices on the edge of the cake immediately before serving. Decorate with mint if desired.
Tip: If you want to leave the kiwi slices on the cake longer, blanch the fruit beforehand. In combination with yoghurt, quark and cream they become bitter