Melt the butter. Put the lady fingers in a freezer bag, close it and crumble finely with the help of the rolling pin. Pour into a bowl, add melted butter and mix well. Grease the bottom of a springform pan (26 cm Ø).
Spread the crumb mixture in it and press it down to a base with your hands. Cover the base and chill for about 1 hour.
In the meantime, soak 4 and 8 sheets of gelatine separately in cold water. Puree the mango with the juice in a tall mixing bowl with the hand blender's blender. Squeeze 4 sheets of gelatine and melt them in a small pot.
Stir in 4 tablespoons of mango puree and stir into the rest of the puree. Set aside.
Mix yoghurt, sugar, vanilla sugar and lemon juice. Squeeze 8 sheets of gelatine, also melt in a small pot, stir in 3 tbsp. yoghurt cream and stir into the rest of the cream. Chill for about 5 minutes until the mixture begins to gel.
In the meantime, whip the cream until stiff with the whisks of the hand mixer. Fold into the yoghurt cream in portions. Spread the cream alternately with the mango puree on the cake base. Pull through spirally with a fork.
Put the cake in a cool place for at least 4 hours. Cut the mango off the stone. Peel and chop the flesh. Remove the cake from the tin, place on a cake plate and decorate with mango and mint.