Line the bottom of a springform pan with parchment paper. Lightly grease the sides if desired.

Crush the cookies in a blender or food processor. If you don’t have one, you can place them in a bowl and crush them by hand. Melt the butter and mix it with the cookie crumbs. Press the mixture firmly into the bottom of the pan using the back of a spoon. Place the crust in the refrigerator to chill.

Melt the Toblerone and dark chocolate using a double boiler (au bain-marie). Set aside to cool slightly.

Beat the cream cheese until smooth. In a separate bowl, whip the heavy cream until it thickens (but not stiff peaks). Add the whipped cream and mascarpone to the cream cheese and mix until smooth.

Add the melted chocolate and mix until the filling is evenly combined and smooth. Pour the filling over the crust and refrigerate for at least 8 hours, or until set.

For decoration, chop the Toblerone into pieces and scatter over the cheesecake just before serving.