• Grease a 9-inch springform pan and line the bottom with parchment paper.
• Preheat the oven to 325°F.
• In the bowl of a food processor, pulse the Oreo cookies until small crumbs form. Add the melted butter and pulse until the mixture is evenly combined.
• Press the cookie crumble into the prepared springform pan and set aside.
• In a mixing bowl, beat the cream cheese, peanut butter, and sugar together until light and fluffy.
• Add the vanilla, sour cream, heavy cream, and flour and beat again until well combined.
• By hand, mix in the eggs, one at a time. Stir gently to prevent extra air from getting into the mixture.
• Pour the cheesecake mixture into the prepared crust and smooth to level it off.
• Wrap the springform pan with at least two layers of aluminum foil to ensure it is fully sealed, and no water will get in.
• Place the wrapped pan in a larger pan and fill halfway with hot or boiling water.
• Bake for 65 to 75 minutes. The cheesecake should appear matte across the top surface, and the center should be slightly jiggly.
• Turn off the oven, keeping the door closed for 20 minutes. After 20 minutes, crack the oven door and leave the cheesecake in place for another 20 minutes.
• Remove the cheesecake from the oven. Allow it to cool the rest of the way and then transfer to the refrigerator to chill for at least 3 additional hours.

Ganache

• Heat the heavy cream until simmering. Pour over the chocolate chips, placing a plate or lid over the mixture to trap the heat. Let the mixture sit for several minutes, then whisk together vigorously until a silky, thick chocolate ganache comes together.

Frosting

• Beat together the butter and peanut butter until smooth.
• Beat in the powdered sugar. The mixture will be crumbly and very thick.
• While beating, add in the heavy cream, 1 to 2 tablespoons at a time, until a fluffy frosting forms.
• Place the frosting in a piping bag fitted with a large star tip.

Assembly

• Run a knife around the edges of the chilled cheesecake to loosen it from the springform pan. Remove the ring from the pan and transfer the cheesecake to a serving platter, if desired.
• Pour the chocolate ganache over the center of the cheesecake, spreading it with an offset spatula and allowing some of the ganache to drip down the sides of the cheesecake.
• Allow the ganache to set for 10 to 15 minutes.
• Pipe swirls around the top edge of the cheesecake with the peanut butter frosting.
• Decorate with buckeye balls on top of the frosting.