Melt the butter. Put the butter biscuits in a freezer bag and crumble them finely with a cake roll. Add crumbs to the butter and press them onto the bottom of a springform pan (26 cm Ø). Refrigerate the base for about 30 minutes. Soak gelatine in cold water. Mix yoghurt, sugar and vanillin sugar. Sort and clean the raspberries.
Puree 150 g raspberries, pass through a sieve and stir into the yoghurt. Squeeze out the gelatine, dissolve and mix with 4 tablespoons of cream, then stir into the rest of the cream. Whip the cream until stiff. First mix 100 g raspberries and then the cream into the yoghurt cream. Fill the cream into the springform pan and smooth it down. Chill the cake for at least 2 hours. Decorate the cake pieces with about 100 g raspberries and mint