Finely crush the Oreo cookies with a food processor or blender to create fine crumbs.
In a medium-sized bowl, combine the Oreo crumbs, melted butter, and a pinch of salt until well mixed.
Using your hand or a flat bottomed cup, press this mixture into the bottom and sides of a tart pan with a removable bottom.
Freeze the crust for at least 10 minutes to set. While the crust is in the freezer, make the filling
For the Filling:
Using a eletric hand mixer, cream the unsalted butter on high speed until it becomes light and fluffy (about 2 minutes).
Scrape down the sides of the bowl, add the creamy peanut butter, and beat on medium-high speed until the mixture is light and fluffy, and the volume has increased.
Add the powdered sugar, salt, cinnamon and mix on medium until fully combined.
Pour the filling into the chilled cookie crust, and using the back of a spoon, spread it evenly.
Place the pie back into the freezer while you prepare the ganache.
For the Ganache Topping:
Heat the heavy cream in a medium microwave-safe bowl until it's hot and slightly bubbly. Start with 30 seconds and check, as it may take longer depending on your microwave.
Remove from the microwave and add the semi-sweet chocolate chips. Let it sit for at least 3 minutes; you can cover it with plastic wrap to expedite the process.
Stir until everything melts and the mixture is smooth.
Spread the chocolate ganache evenly over the cooled peanut butter filling using the back of a spoon or a small offset spatula.
Sprinkle a pinch of flaky salt over the ganache for a finishing touch.
Cover and refrigerate for at least 2 hour or until ready to serve.