Preheat oven to 350 F.
Wrap the outside of an 8 or 9 inch springform pan with two layers of aluminum foil, and bring the foil up the sides of the pan, making sure it’s tight enough that no water gets in during the baking process.
Grease the inside of the pan with nonstick cooking spray and line the bottom of the pan with parchment paper.
Mix together Oreo crumbs and melted butter. Press the mixture into the bottom of your springform pan, making a smooth and even layer. Set aside.
With electric mixer, mix cream cheese and sugar on medium speed until smooth. Decrease the speed to low and add eggs one at a time. Add sour cream, vanilla extract, and lemon juice and mix until well incorporated.
Spread 1 ½ cup of cheesecake filling onto Oreo crust and smooth with a spatula. Place in the freezer for 10-15 minutes.
Meanwhile, add pumpkin pure, cinnamon, nutmeg, and cloves to the remaining cheesecake filling and mix until well incorporated. Spread evenly onto plain cheesecake filling once it comes out of the freezer.
Place springform pan in a roasting pan, then fill roasting pan about a quarter of the way with hot water, and bake at 350 degrees for 55-65 minutes, rotating once halfway through. The cheesecake should be set around the edges and slightly loose in the center. (I used an 8 inch springform pan, so I had to bake the cake almost 1 hour 30 minutes to set.)
Remove springform pan from the water bath and set on a cooling rack to cool, then remove aluminum foil and refrigerate (at least 5 hours or overnight). Once it’s completely cooled, run a thin knife around the edge and remove the ring from the springform pan.
Beat 1 ½ cup heavy cream and powdered sugar until stiff peaks form. Spread 1⅓ cup whipped cream on top of pumpkin cheesecake and save the rest for garnish. Place the cake in the freezer for 20 minutes.
Over double boiler, melt chopped chocolate until completely smooth and has no lumps, then stir in ½ cup heavy whipping cream (from the fridge). If the ganache is warm, set aside to cool (be sure not to spread warm chocolate ganache over the whipped cream because the cream will begin to melt and mix with chocolate). When it's cooled completely, spread about ⅔ of the ganache onto cake to completely cover the whipped cream layer, then set the cake in the freezer for 5-10 minutes. Reheat the rest of ganache and pour it over the cake and let it drip over the edge. Let it cool completely to set, then garnish the cake with heavy cream dollops and chocolate chips.
Store the cake in the fridge.