Melt the butter at a mild heat. Put the lady fingers in a freezer bag and close it. Crumble finely with a rolling pin and mix with the butter. Place a cake ring or the edge of a springform pan (26 cm Ø) on a cake plate lightly coated with oil. Pour in the sponge finger mixture as a cake base and press it down. Chill for about 1 hour.
Soak 5 and 8 gelatine leaves separately in cold water. Puree the mango and juice. Squeeze 5 sheets of gelatine and dissolve over a mild heat. Stir in 4 tablespoons of mango puree, then stir into the rest of the puree. Do not chill
Mix yoghurt, 100 g sugar, vanillin sugar and lemon juice. Squeeze 8 sheets of gelatine, dissolve over a mild heat. Stir in 3 tbsp. yoghurt cream and then stir into the rest of the yoghurt cream. Chill for approx. 5 minutes until it starts to gel
Whip 300 g cream until stiff. Fold into the yoghurt cream. Spread half the cream first, then half the puree on the cake base. Draw the yoghurt and puree mass spirally with a fork in a marble-like pattern. Spread the rest of the yoghurt cream and then the rest of the puree on top and marble. Chill for about 5 hours.
Whip 100 g cream until stiff, pouring in 1 teaspoon of sugar. Decorate cake with cream etc.