Make the Crust: Preheat oven to 350° F. Spray a 9-inch springform pan with nonstick spray and make sure the bottom is securely fastened. Pulse oreos in a food processor until you have fine crumbs. Stir together crumbs and melted butter. Press into prepared pan and up the sides a bit. Bake this for 10 minutes. Set aside. Keep the oven on at 350.

Make the Cheesecake Filling: In a large mixing bowl, beat the softened cream cheese with electric mixer until creamy, about 1-2 minutes. Beat in the peanut butter, until completely combined and creamy. Add the sugar & mix until well incorporated, about 1 minute. Scrape the sides of the bowl with a rubber spatula as you go. Add the eggs one at a time, mixing on medium speed after each until just incorporated. Add the vanilla, sour cream, corn starch, and salt and mix until just combined.

Prepare the Water Bath: Bring the large pot of water to a boil. Set your springform pan on a rack positioned in the center of the oven, and place the roasting pan on the rack below. Pour the boiling water into the roasting pan.

Assemble & Bake Cheesecake: Pour the batter over your prepared crust. Bake the cheesecake for 74 to 85 minutes. When done, the cheesecake will have only a slight wobble in the center. Turn off the oven and crack the oven door open. Let the cheesecake cool in the oven for 1 hour before removing it.

Cheesecake Cooling: Once the hour is up, remove the pan from the oven. Let cool to room temperature, about 1 hour more, then cover with foil and refrigerate at least 6 hours or up to 1 day before removing from the pan and serving.

Make the Ganache: Add finely chopped chocolate to a small bowl. Heat heavy cream in a small saucepan over medium high heat until simmering. Pour over the chocolate, let sit for 4 minutes, then stir until completely smooth. Pour over the center of the cheesecake.

Make the Peanut Butter Whipped Cream: Add the water to a small bowl and sprinkle the powdered gelatin on top. Let stand for 3 minutes. Then, microwave for 4-5 seconds. Add whipped cream ingredients to a medium bowl and beat on high speed until it begins to thicken. Stream in the liquid gelatin mixture while you mix on low. Keep mixing until cream is thick but still smooth.

Serve + Store: Add mini peanut butter cups and chopped peanuts if desired. Once decorated, slice, and serve! Store leftovers in an airtight container in the fridge for 3-4 days.