Melt the butter. Coarsely chop the cornflakes and mix with the butter. Grease the bottom and rim of a springform pan (26 cm Ø) and line with baking paper. Spread the mixture over it and press it to a smooth base, chill. Soak gelatine in cold water for about 5 minutes.
Bring half of the lemon juice to the boil with sugar. Squeeze 12 sheets of gelatine and dissolve them in it. Stir in some buttermilk. Stir the lemon-gelatine mixture into the remaining buttermilk. Chill the buttermilk mixture for 10-20 minutes. In the meantime drain the mango and puree it finely with the hand blender. Stir in the rest of the lemon juice. Squeeze 2 sheets of gelatine, dissolve and stir into the mango puree drop by drop. Whip the cream until stiff and chill. As soon as the buttermilk begins to gel, fold in the cream.
In the meantime drain the mango and puree it finely with the hand blender. Stir in the rest of the lemon juice. Squeeze 2 sheets of gelatine, dissolve and stir into the mango puree drop by drop. Whip the cream until stiff and chill. As soon as the buttermilk begins to gel, fold in the cream. Then briefly fold in the frozen raspberries and the mango sauce and spread on the cornflake base. Chill the cake for 3-4 hours
waiting time approx. 4 hours