Open each Oreo cookie and separate the biscuits from the filling. Place the filling in one bowl and the cookies in another. Crush the biscuits in a food processor. Melt the butter and add it to the crushed biscuits. Combine and spread the biscuit base over a springform pan. Place in the freezer for the time being.
Melt the chocolate in a double boiler. I recommend the use of 70% dark chocolate for the best taste in the end product. In the bowl with the Oreo filling add the cream cheese and powdered sugar. Mix with an electric mixer at medium speed until combined. When the melted chocolate has reached room temperature, add that to cream cheese mix and combine.
Soak the gelatin sheets in cold water until soft, for a couple of minutes. Warm up 100 ml of cream and stir in the soaked gelatin to melt. Combine with the rest of the cream. Slowly pour the cream into cream cheese and chocolate mixture, mixing at low speed. Stop when the mixture is even and combined.
Take the crust out of the freezer and spread a thin layer of raspberry jam on its surpface, making sure to keep about 1 cm away from the edges. Pour the chocolate and cream cheese mixture on the crust and even out the top with a spatula. Place in the fridge and let set for a minimum of 2 hours (overnight is preferred).
To make the ganache, warm up the whipping cream and take away from the heat just before it reaches boiling temperature. Crack the chocolate and add it to the hot cream. Stir until combined. Let sit until it reaches room temperature, the pour over the cheesecake, letting it gently drop down the sides. Decorate with freeze-dried raspberries.