Preheat oven to 350°F and line the bottom of a 9" spring-form pan with parchment paper.
Make the crust: Place the Oreo cookies, with the white filling, into a food processor and pulse until finely crushed. Add the melted butter and pulse until fully combined. Press the mixture firmly into the bottom of the spring-form pan. Bake for 10 minutes, remove and set aside while making the filling.
Prepare the water bath: Turn the oven down to 320°F. Place a large roasting pan in the oven on the middle rack. Pour hot water into the pan, making sure it is about 1" in depth. Close the oven door. (See notes)
Make the filling: Beat the cream cheese, butter and granulated sugar on low speed with an electric mixer until it is smooth and creamy. Scrape down the sides of the bowl. Add the eggs, one at a time, fully incorporating before adding the next egg. Scrape down the sides of the bowl and then add the sour cream, vanilla extract and pinch of salt, mixing until smooth. Gently fold the crushed Oreos into the batter with a spatula.
Bake: Pour the filling into the spring-form pan and smooth the top with an off-set spatula. Insert the spring-form pan into a 10" cake pan and place the cake pan into the water bath. Bake for 1 hour. (Water level should cover half the depth of the cake pan. Add water if needed.)
Cool: Turn the oven off, crack the door and allow the cheesecake to cool inside of the oven for 1 hour. Remove the cheesecake, run a sharp knife around the edge of the pan to help release the sides of the cheesecake and allow to cool completely on the counter.
Chill: Place the uncovered cheesecake in the refrigerator overnight or a minimum of 6 hours to firm up. (Do not remove the spring-form pan.)
Make the ganache: Place the chocolate and heavy cream in a microwave safe bowl and microwave on high for 1 minute. Remove the bowl from microwave and let sit for 3-5 minutes to allow the chocolate to melt in the cream. Stir the mixture until it is smooth and allow to come to room temperature. Smooth the ganache on top of the cheesecake and place back it into the refrigerator for a minimum of 30 minutes.
Serve: When ready to serve, take the cheesecake out of the refrigerator and remove the spring-form pan. Pipe dollops of whipped cream over the top of the cheesecake and decorate with half slices of Oreos.