For the layer, crumble the biscuits, melt the butter and add the brown sugar to it. Mix the biscuits with the sugar. Form the cake layer in an 8 form. Put the form in the fridge to harden.
For the cream mixture, activate the gelatin by adding 3 1/3 tbsp (50 ml) cold water to it. Leave it to activate for 10 min. Mix together the cream cheese, sour cream, 3 1/3 tbsp (50 ml) cream and the vanilla with a mixer.
In a pan, heat the remaining cream until simmering. Add in the chocolate, wait 5 min. for it to melt. Add the gelatin and stir well. Pour the chocolate mixture to the other one. Beat with a mixer.
Pour all of the mixture over the cake layer in the form, even it out. Cover with foil and put in the fridge for 3-4 hours to harden.